ST75C530 ,SUPER INTEGRATED DEVICES WITH DSP, AFE & MEMORIES FOR TELEPHONY, MODEM, FAX OVER INTERNET & POTS LINESFEATURESSingle Chip Fax Handset Mode- ITU-T V.17, V.29, V.27ter, V.21 with Fax support - Rx and Tx ..
ST75C540 ,SUPER INTEGRATED DEVICES WITH DSP, AFE & MEMORIES FOR TELEPHONY, MODEM, FAX OVER INTERNET & POTS LINESFUNCTIONAL DESCRIPTION . . . . 13V.1 SYSTEM ARCHITECTURE . . . . . . 13V.2 MODES OF OPERA ..
ST75C540FP-A ,SUPER INTEGRATED DEVICESWITH DSP, AFE & MEMORIES FORTELEPHONY,MODEM, FAXOVERINTERNET& POTSLINESFUNCTIONAL DESCRIPTION. .... ... ... .... .. .. .. .... .. .. .. .... .. .. .. ... 13V.1 SYSTEM ARC ..
ST763 ,3.3V STEP DOWN CURRENT MODE PWM DC-DC CONVERTERSAbsolute Maximum Ratings are those values beyond which damage to the device may occur. Functional o ..
ST763A ,3.3V STEP DOWN CURRENT MODE PWM DC-DC CONVERTERSABSOLUTE MAXIMUM RATINGS Symbol Parameter² Value UnitV DC Input Voltage-0.3 to 12 VCCV Switch ..
ST763ACD ,3.3V STEP DOWN CURRENT MODE PWM DC-DC CONVERTERSAbsolute Maximum Ratings are those values beyond which damage to the device may occur. Functional o ..
STR-A6159 , Universal-Input/13 or 16 W Flyback Switching Regulators
STR-A6159 , Universal-Input/13 or 16 W Flyback Switching Regulators
STR-A6169 , Universal-Input/5 W Flyback Switching Regulator
STR-A6169 , Universal-Input/5 W Flyback Switching Regulator
STR-A6169 , Universal-Input/5 W Flyback Switching Regulator
STR-A6251 , Universal-Input/15 W 50 kHz Flyback Switching Regulators
ST75C530-ST75C540
SUPER INTEGRATED DEVICES WITH DSP, AFE & MEMORIES FOR TELEPHONY, MODEM, FAX OVER INTERNET & POTS LINES
ST75C530
ST75C540SUPER INTEGRA TED DEVICES WITH DSP , AFE & MEMORIES
FOR TELEPHONY , MODEM, F AX OVER INTERNET & POTS LINES
February 1999
SUMMARIZED FEATURES(for detailed features, see page 4). SINGLE CHIP FAX Up to 14.4Kbps (V.17). FULL DUPLEX DATA MODEM UP TO
14.4Kbps (V.32Bis). DIGITAL ANSWERING MACHINE :
- 4.8Kbps VOCODER
- V ARIABLE PLAYBACK SPEED (+50% to -50%)
- ADPCM 32, 34, 16Kbps VOCODER. FULL-DUPLEX DIGITAL SPEAKERPHONE
WITH ECHO CANCELLATION. PROGRAMMABLE RING DETECTION. 16 PROGRAMMABLE TONE DETECTORS
FOR CLID AND SCWID. DTMF DETECTION. VERSATILE HOST INTERFACES. 16 GENERAL PURPOSE I/O PORTS. 2 RELAY DRIVE OUTPUTS. SINGLE 5V POWER SUPPLY. TYPICAL ACTIVE POWER CONSUMPTION :
650mW (ST75C530), 750 mW (ST75C540) . LOW POWER MODE < 30mW. 80-PIN TQFP PACKAGE (14mm x 14mm)
DESCRIPTIONST75C530 and ST75C540 are two super-inte-
grated devices including DSP, Modem and Audio
Analog Front Ends and memories for Telephony,
Modem and FAX applications.
These devices can be used for classical applica-
tions over POTS lines or over Internet.
The super integration technology allows a signifi-
cant cost reduction on bill of materials for equip-
ment like High-End phones, INTERNET phones,
phone-Fax, INTERNET FAX, ...
The devices are used with a host processor
through a Dual Port RAM allowing the use of any
kind of microcontroller (RISC, CISC, General Pur-
pose 8-bit μC, ...).
The embedded software includes : handset with listening group capability, full duplex handsfree, voice coder/decoder at 4.8Kbps for static answer-
ing machine applications and ADPCM 16Kbps,
24Kbps and 32Kbps for high quality message
recording, Tone and DTMF generators, Tone and DTMF detectors, FAX up to 14.4Kbps, Data-Modem up to 14.4Kbps (ST75C540 only).
The DSP sofware is extensively user configurable
allowing specific functions to be supported like
Caller Identifier (CLID) and Second Call Waiting
Identifier (SCWID).
The DSP software includes a transparent mode
allowing the host controller to access directly the
modem Analog Front End and the Audio AFE
through the dual Port RAM. This is very useful for
hostprocessing modem solutions (or soft modem)
where the modulation and the demodulation (V.34,
V.90) are done by the application main processor.
In transparent mode, the embedded DSP can be
used simultaneously with the same samples.
The transparent mode for audio AFE is provided to
play audio files or to record voice and/or audio.
1/84
CONTENTS Page DETAILED FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
PIN DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
II.1 PIN CONNECTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
II.2 HOST INTERFACE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
II.3 ANALOG INTERFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
II.4 GENERAL PURPOSE IO AND RELAY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
II.5 MISCELLANEOUS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
II.6 POWER SUPPLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
III BLOCK DIAGRAMS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
III.1 ANALOG INTERFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
III.2 INTERNAL BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
ELECTRICAL SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
IV.1 MAXIMUM RATINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
IV.2 RECOMMENDED OPERATING CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
IV.3 DIGITAL INTERFACE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
IV.4 MODEM ANALOG INTERFACE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
IV.5 AUDIO ANALOG INTERFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
IV.6 AC CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
FUNCTIONAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
V.1 SYSTEM ARCHITECTURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
V.2 MODES OF OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
V.3 OPERATIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
V.3.1 Modem Transmitter Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
V.3.2 Modem Receiver Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
V.3.3 Tone Generator Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
V.3.4 Tone Detector Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
V.3.5 V.21 Channel 2 Flag Detector Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
V.3.6 HDLC Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
V.3.7 UART Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
V.3.8 DTMF Detector Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
V.3.9 Ring Detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
V.3.10 VOCODER Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
V.3.11 Voice Activity Detector (VAD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
V.3.12 Telephony Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
V.3.13 Low Power Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
V.3.14 Reset. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
V.4 MODEM INTERFACE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
V.4.1 Analog Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
V.4.2 General I/O and Relay Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
V.4.3 Crystal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
V.4.4 Typical Application Schematic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
V.4.5 Host Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
USER INTERFACE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
VI.1 DUAL PORT RAM DESCRIPTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
VI.2 COMMAND SET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
VI.3 COMMAND SET SHORT FORM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
VI.4 STATUS - REPORTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
VI.5 DATA EXCHANGES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
ST75C530 - ST75C5402/84
VII COMMAND SET DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
VIII STATUS DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
VIII.1 COMMAND ACKNOWLEDGE AND REPORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
VIII.2 MODEM STATUS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
TONE DETECTORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
IX.1 OVERVIEW. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
IX.2 DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
IX.3 EXAMPLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
PARALLEL DATA EXCHANGE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
X.1 OVERVIEW. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
X.2 TRANSMIT BUFFER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
X.3 RECEIVE BUFFER. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
X.4 INTERRUPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
X.5 DATA FORMAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
X.6 FORM COMMAND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
TRANSMITTING DATA IN PARALLEL MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
XI.1 DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
XI.2 MODEM FLOW CHART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
XI.3 HOST FLOW CHART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
XI.4 ERROR DETECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
XI.5 SYNCHRONOUS MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
XI.6 HDLC MODE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
XI.7 UART MODE DESCRIPTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
XII RECEIVING IN PARALLEL MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
XII.1 DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
XII.2 MODEM FLOW CHART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
XII.3 HOST FLOW CHART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
XII.4 ERROR DETECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
XII.5 SYNCHRONOUS MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
XII.6 HDLC MODE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
XII.7 UART MODE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
XIII VOCODER DATA EXCHANGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
XIII.1 OVERVIEW. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
XIII.2 VOCODER BUFFER. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
XIII.3 TRANSMIT (DECODER) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
XIII.4 RECEIVE (CODER) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
XIV TRANSPARENT MODE DATA EXCHANGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
DEFAULT CALL PROGRESS TONE DETECTORS . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
XVI DEFAULT ANSWER TONE DETECTORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
XVII ELECTRICAL SCHEMATICS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
XVIII PCB DESIGN GUIDELINES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
XIX APPENDIX A : MODES OF OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
PACKAGE MECHANICAL DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
ST75C530 - ST75C5403/84
I - DETAILED FEATURES
Single Chip Fax ITU-T V.17, V.29, V.27ter, V.21 with Fax support V.17, V.29 (T104), V.27ter short trains,
V.33 half-duplex V.21 flag detection and 4 tone detection during
high speed reception modes V.21 flag detection, DTMF detection and 4
tone detection duringV.21 channel 2 reception
modes Programmable call progress and call waiting
detection Parallel data handling HDLC and UART framing support 1700Hz and 1800Hz carrier Full implementation of the V.17, V.33, V.29 and
V.27 handshakes 0 to -15dBm programmable transmit power 0 to -47dBm receiver dynamic range (ST75C530)
0 to -45dBm receiver dynamic range (ST75C540)
Full Duplex Data Modem ITU-T V.32bis, V.32 (14400, 12000, 9600, 7200,
4800bps) (*) Maximum round trip delay : 1.2s (satellite hops)
(*) Up to 10Hz of phase roll on far end echo (*) ITU-T V.22bis, V.22 (2400, 1200bps) (*) V.32bis/V.32/V.22bis/V.22 automode (*) ITU- V.23, V.21, bell 103 full-duplex,
Bell202 demodulator -10 to -25dBm programmable transmit power -10 to -38dBm receiver dynamic range (*) HDLC and UART framing support Train based on quality line sampling (*)
(*) ST75C540 only
Digital Answering Machine Low bit rate speech coder (4800bps) Variable playback speed (+50% to -50%) ARAM compatibility (error correction) ADPCM 32, 24, 16Kbps Line echo cancellation Voice activity detector Concurrent DTMF and tone detection
Handset Mode Rx and Tx AGC versus line current for line
losses compensation comply with most of
country regulations Dynamic limiter in transmit path to prevent
distortion Two way conversation recording
Hands-free Mode Full duplex speakerphone using LMS adaptative
filtering including line echo cancellation and
acoustic echo cancellation Rx and Tx AGC versus line current for line
losses compensation comply with most of
country regulations Dynamic limiter in transmit path to prevent
distortion Loudspeaker volume control Two way conversation recording
Extended Modes of Operations Programmable ring detection 16 programmable tone detectors Tone and DTMF generators Caller ID reception Transparent mode allowing direct transfer of Mo-
dem AFE and audio AFE samples to and from
host processor for soft Modem applications and
sound files playing DTMF detection Wide dynamic range (>48dB)
Versatile Interfaces Parallel 128 x 8-bit dual port RAM General purpose 16 I/O ports 2 relay drive outputs Full diagnostic capability Dual 8-bit DAC for constellation display
Single 5V Power Supply Typical active power consumption :
650mW (ST75C530), 725mW (ST75C540) Low power mode < 30mW
ST75C530 - ST75C5404/84
II - PIN DESCRIPTION
II.1 - Pin Connections
ST75C530 - ST75C5405/84
II.2 - Host InterfaceThe exchanges with the control processor proceed through a 128 x 8 DUAL port RAM shared between the
ST75C530/540 and the Host. The signals associated with this interface are :
II.3 - Analog Interface
II.4 - General Purpose IO and Relay
II - PIN DESCRIPTION (continued)
ST75C530 - ST75C5406/84
II.5 - Miscellaneous
Note : The nominal frequency of the crystal oscillator is 44.2368MHz with a precision better than ± 100ppm.
II.6 - Power Supply
II - PIN DESCRIPTION (continued)
ST75C530 - ST75C5407/84
III - BLOCK DIAGRAMS
III.1 - Analog Interface
III.2 - Internal Block Diagram
ST75C530 - ST75C5408/84
IV - ELECTRICAL SPECIFICATIONS
IV.1 - Maximum Ratings (AGND = DGND = RGND = 0V, all voltages with respect to 0V)Warning : Operation beyond these limits may result in permanent damage to the device. Normal operation is not guaranted at these extremes.
IV.2 - Recommended Operating Conditions(AGND = DGND = RGND = 0V, all voltages with respect to 0V)
Note 1 : DC current only. If dynamic load exists, the VCM output must be buffered or the performances of ADCs and DACs will be degraded.
ST75C530 - ST75C5409/84
IV.3 - Digital Interface(AVDD = DVDD = 5V, AGND = DGND = RGND = 0V) except XTAL, EXTAL, RING.
CRYSTAL OSCILLATOR
RING (this input have hysteresis)
IV - ELECTRICAL SPECIFICATIONS (continued)
ST75C530 - ST75C54010/84
IV.4 - Modem Analog InterfaceAVDD = DVDD = 5V, Tamb = 25oC
Measurement bandwidth is flat from 100Hz to 4800Hz ;Load impedance 10kΩ, 20pF
For differential output (TxA1/TxA2) : 0dBr = 1.77VRMS 1kHz sinwave (equivalent to 5VPP).
For single input (RxA) : 0dBr = 886mVRMS 1kHz sinwave (equivalent to 2.5VPP).
IV.5 - Audio Analog InterfaceAVDD = DVDD = 5V, Tamb = 25oC
Measurement bandwidth is flat from 100Hz to 4800Hz ;Load impedance 10kΩ, 20pF
For differential output (SPK1N/SPK1P, SPK2N/SPK2P , SPK3N/SPK3P) : 0dBr = 1.77VRMS 1kHz sinwave
(equivalent to 5VPP).
For single input (MIC1, MIC2, MIC3) : 0dBr = 886mVRMS 1kHz sinwave (equivalent to 2.5VPP).
IV - ELECTRICAL SPECIFICATIONS (continued)
ST75C530 - ST75C54011/84
IV.6 - AC Electrical Characteristics
IV - ELECTRICAL SPECIFICATIONS (continued)
ST75C530 - ST75C54012/84
V - FUNCTIONAL DESCRIPTION
V.1 - System ArchitectureThe chip allows the design of a complete FAX, Data
Modem, Hands-Free Telephone and Answering
Machine system. A versatile dual port RAM allows
an easy interface with most micro-controllers.
V.2 - Modes of OperationRefer to Appendix A for Block Diagrams.
V.3 - Operations
V.3.1 - Modem Transmitter DescriptionThe signal pulses are shaped in a dedicated filter
further combined with a compromise transmit
equalizer suited for transmission over strongly dis-
torted lines. 3 different compromise equalizers are
available and can be selected by software.
V.3.2 - Modem Receiver DescriptionThe receiver section handles complex signals and
uses a fractionally spaced complex equalizer. It is
able to cope with distant modem timing drifts up to-4 as specified in the ITU-T recommendations. It
also compensates for frequency drift up to 10Hz
and for phase jitter at multiple and simultaneous
frequencies.
V.3.3 - Tone Generator DescriptionFour tones can be simultaneously generated by the
ST75C530/540. These tones are determined by
their frequencies and by the output amplitude level.
A set of specific commands are also available for
DTMF generation. Any of the 4 tone generators can
be output independently either on the Audio DAC
or the line DAC.
V.3.4 - Tone Detector DescriptionDuring TONE (respectively TONECID) Mode six-
teen (respectively eight) tones can be simultane-
ously detected by the ST75C530/540. Each of the
tones to be detected is defined by the coefficients
of a 4th order programmable IIR. Detection thresh-
olds are programmable from -51dBm up to -6dBm.
These primary detectors can detect tone up to
3.3kHz (sampling rate 7.2kHz in all modes). They
also have a programmable internal wiring feature
(see Chapter IX).
In all modes, except Handset (HANDSET) and Full
Duplex V.32bis/V.32/V.22bis/V.22 (Modem)
modes, 4 additional tone detectors (each of them
being a 4th order programmable IIR) are concur-
rently running. In Handset mode only 2 additional
tone detectors are available. Detection thresholds
are programmable from -51dBm up to -6dBm. This
secondary programmable detector can detect
tones up to 1.8kHz by default set-up with a sam-
pling rate at 4.8kHz. But this 4 additional tone
detectors can also detect tones up to 3.3kHz with
a sampling rate at 9.6kHz. In order to avoid wrong
detectgion, relative detectgion is also provided.
V.3.5 - V.21 Channel 2 Flag Detector DescriptionIn all the Receive FAX Modes, including V.21 Chan-
nel 2 Mode, the ST75C530/540 processes a V.21
Flag “7E” detector, either in the idle state, the train
sequence or the data mode. The detection time is
3 consecutive flags to detect and 1 byte to loose
the detection.
V.3.6 - HDLC DescriptionIn all FAX Modes (MODEM), including V.21 Chan-
nel 2 Mode, and also Full Duplex
V.32bis/V.32/V.22bis/V.22 (Modem) modes, a
HDLC framing and deframing is supported by the
ST75C530/540. The number of transmitted flags
can be programmed.
V.3.7 - UART DescriptionIn Full Duplex V.32bis/V.32/V.22bis/V.22 Modem
Modes and TONECID V.23 receive mode, a parallel
UART is performed by the ST75C530/540. This
UART manage the Break signal either at the trans-
mit and the receive bit stream. The Data format
supported are 7 and 8 bit of Data; even, odd or no
Parity, 1 or 2 stop bits.
V.3.8 - DTMF Detector DescriptionA DTMF Detector is included in the ST75C530/540,
it allows detection of valid DTMF Digits. A valid
DTMF Digit is defined as a dual tone with a total
power higher than -43dBm, a duration higher than
40ms and a differential amplitude within ±8dB. This
DTMF Detector is enabled in all modes except in
Fax Modem, Data Modem and Handset modes. It
is also enabled in V.21 Channel 2 Receive Mode.
The DTMF thresholds and duration can be
changed from they default value by overwriting
DSP’s RAM locations. In the default setup, this
detector is compliant with the NET4 standard. The
frequency deviation can be changed by overwriting
the default DTMF’s filters coefficients.
V.3.9 - Ring DetectorThis detector detects RING signal from 15Hz to
68Hz, it can be programmed to expand the mini-
mum and maximum detection frequency up to
12Hz (for min) and 144Hz (for max). The detection
time is equal to one period of the ring signal, and
the loose time to the minimum between one period
of the ring signal and the inverse of the minimum
frequency.
The associated STA_RING status is as Figure 1.
ST75C530 - ST75C54013/84
V.3.10 - VOCODER DescriptionThe Vocoder mode allows the implementation of
an answering machine function. In the CODER
mode the received samples from one of the two
analog inputs, Line or Audio, are compressed by
the ST75C530/540 and written into the dual port
RAM Vocoder Buffer (VOCxxx). At the same time
the ST75C530/540 is looking for an incoming
DTMF tone and 4 different programmable tones.
In the DECODER mode the compressed samples
are read from the dual port RAM, decompressed
and transmitted to one of the two analog output,
Line or Micx. The ST75C530/540 synthesises an
estimation of its echo and subtracts it from the
received signal. At the same time the
ST75C530/540 is looking for an incoming DTMF
tone and 4 different tones.
Two algorithms of voice coding are implemented : Low bit rate speech coder (4800bps or 5300bps
with forward error correction). ADPCM (ST proprietary algorithm) at 32, 24 and
16Kbps.
If the low bit rate coder algorithm is selected the
ST75C530/540 has the capability to slow down or
speed up the DECODER flow up to ±50%. This
function allows a quick message listening if speed
up is used, or at the opposite if slow down is used,
an enhancement of the voice intelligibility.
V.3.11 - Voice Activity Detector (VAD)In CODER Mode, for both of the Voice Coding
algorithms, a Voice Activity Detector is imple-
mented while coding by the ST75C530/540. The
STA_109 bit and STA_109F bit reflect the state of
the VAD. After the CONF command the VAD is on
(assume voice). The default time-out to detect si-
lence is 2 seconds and the set-up time to detect the
voice is 15ms. This VAD information is also copied
into the Receive Buffer Status Word MSB (VOC-
STA bit7). This detector is fully programmable in
level sensitivity (down to -60dBm), hysteresis, and
various criteria.
An optional silence suppressor is implemented in
the Coder section to suppress long silence in the
incoming message. When enabled (CONF_SUP-
SIL equal 1) if a long silence is detected (STA_109
equal 0) the ST75C530/540 stops generating Buff-
er Interrupts. After that if a voice is again detected
the ST75C530/540 will resume the Buffer Interrupt
mechanism.
Figure 1
V - FUNCTIONAL DESCRIPTION (continued)
Figure 2
ST75C530 - ST75C54014/84
V.3.12 - Telephony FunctionsST75C530/540 telephony software provides both
handset and handsfree modes. ST75C530/540 is
connected to the phone line through a D.A.A.,
handset and loudspeaker are connected to
ST75C530/540 through amplifiers.
Though the D.A.A. has to comply with modem/fax
regulations in most of the applications, the micro-
phone and the earphone amplifier gains will be
adjusted in compliance with the telephony regula-
tions. The software implemented in ST75C530/540
allows functions such as softclipping, AGC in both
modes, and full duplex mode in handsfree (see Fig-
ure 3).
V.3.12.1 - Handset ModeIn handset mode, all the attenuations (_SPKGAIN,
_TXGAIN, _MIKGAIN) are from 0dB to -inf
(32768 steps). AGC and softclipping functions can
be enabled and disabled by software (see Figure 4).
Figure 3 : Handset/Handsfree Mode Operation
V - FUNCTIONAL DESCRIPTION (continued)
Figure 4 : Handset Mode
ST75C530 - ST75C54015/84
Tx Characteristics
Rx Characteristics
AGCThe line current information is coming from the
D.A.A. on DP_RING pin (frequency coded informa-
tion using by example a TS555 general purpose
timer). The AGC has a 6dB depth . The attenuation
table can be loaded to comply with each country
regulation. The default table has the following val-
ues. The value of the AGC gain is applied to both
Tx and Rx path (see Table 1).
The address of the table is given in the register
@_TABLE.
The table length is 53. The AGC is enabled using
CONF or MODC command (see paragraph "VII -
COMMAND SET DESCRIPTION".
Once the AGC is running, it is possible to freeze the
AGC gain with the register AGC_FRZ.
SoftclippingThe softclipping introduces a 12dB gain and has a
18dB depth.
The softclipping value is half digital range
(4000 Hex) (see Figure 5).
V - FUNCTIONAL DESCRIPTION (continued)432MICX (mVRMS)3
(mVRMS)D (%)
Tx Softclipping and Distortion2
Figure 5 : Softclipping Static Gain
Table 1 : AGC Gain versus Period Information
ST75C530 - ST75C54016/84
V - FUNCTIONAL DESCRIPTION (continued)
Figure 6 : Handsfree Mode : Full Duplex
V.3.12.2 - Handsfree ModeThe handsfree uses a MIC1 and a SPK1 as microphone and loudspeaker interface (see Figure 6).
Tx Characteristics
Rx Characteristics
AGCThe AGC has the same behavior as in Handset mode. Furthermore, the maximum gain added by AGC can
be fixed by using the RX_GAINMAX and TX_GAINMAX registers.
SoftclippingSee Figure 7.
System StabilityIt is possible to add some gain switching in the Tx and Rx path (to reduce the gain of the loop) by using
the GAIN_RCV and GAIN_XMT registers.
ST75C530 - ST75C54017/84
V - FUNCTIONAL DESCRIPTION (continued)2 103
Rx Softclipping and Distortion
(mVRMS )D (%)32
VMIC2 (mVRMS)
Figure 7 : SPK1 Distortion versus RxAPOWER SPEC1
POWER SPEC2
64Avg
64Avg
0%Ovlp
0%Ovlp
Ftop
Ftop
dBm
RMS
RMS
Vv2
Fxd Y O Hz 5k
Note : Acoustic echo from speaker to microphone input with no
local speech. Receiving speech on line input.
Figure 8 : Speaker and Line Tx Power Spectrums
V.3.13 - Low Power ModeSleep state can be attained by a SLEEP command.
When in sleep mode, the dual port RAM is unavail-
able and the clocks are disabled.
When entering the low power mode, the
ST75C530/540 stops its oscillator, all the peripher-
als of the DSP core are stopped in order to reduce
the power consumption. The dual port RAM is
made inaccessible.
The ST75C530/540 can be awakened by a hard-
ware reset, a RING signal or a dummy write at any
location in the dual port RAM.
There is a maximum time of 20ms to restart the
oscillator after waking up and an additional 5ms
after the interrupt to be able to accept any com-
these initializations are completed, the
ST75C530/540 generates an interrupt IT6 (com-
mand acknoledge) and is programmed to send and
receive tones, the sample clock are programmed to
9600Hz. The total duration of the reset sequence is
about 5ms. After that time the ST75C530/540 is
ready to execute commands sent by the host micro-
controller. The duration of the reset signal should be
greater than 700ns.
are dedicated to Relay driver. The equivalent sche-
matic is as follows : see Figure 9.
Figure 9
ST75C530 - ST75C54018/84
V.4.3 - CrystalThe crystal frequency must be 44.2368MHz for
ST75C530 and 49.152MHz for ST75C540 with an
accuracy better that ±100 ppm. When using a third
harmonic crystal the schematic must be as follow :
see Figure 10.
The crystal features are : third harmonic, parallel, load capacitance = 10pF, æ 100ppm from 0o C to 70oC,
-RS < 50Ω,AT cut (example : SM55-10 MATEL).
Figure 10
V.4.4 - Typical Application SchematicThe Figure 11 is a block diagram designed to allow
transmission of fax signals up to +0dBm and sine
wave up to +6dBm on the telephone line. It allows
reception of fax signals up to 0dBm and sine waves
up to +6dBm. Figure 12 is a block diagram designed
V - FUNCTIONAL DESCRIPTION (continued)
Figure 11
Figure 12to allow transmission of Modem signal up to -
10dBm and reception up to -10dBm. The OPAmps
are +12/0V powered. With this application sche-
matic the out of band transmit spectrum (from 4kHz
to 50kHz) is below -72dBm.
Figures 13 and 14 are examples of application sche-
matics which respects gain value (respectively for fax
and voice application and for Modem application)
and the minimum differential load on TxA1 and TxA2.
V.4.5 - Host InterfaceThe host interface is seen by the micro as a 128x8
RAM, with additional registers accessible through
an 8-bit address space. A selection Pin (INT/MOT)
allows to configure the host bus for either INTEL or
MOTOROLA type control signals.
ST75C530 - ST75C54019/84
V - FUNCTIONAL DESCRIPTION (continued)
Figure 14 : Data Mode
Figure 13 : Fax Mode
ST75C530 - ST75C54020/84
VI - USER INTERFACE
VI.1 - Dual Port Ram DescriptionThe dual port RAM is the standard interface be-
tween the host controller and the ST75C530/540,
for either commands or data. This memory is ad-
dressed through a 7-bit address bus. The locations
from $00 to $3F are RAM location, while locations
from $40 to $60 are control registers dedicated to
the interrupt handling and the general IO port and
Relay output.
Several functional areas are defined in the dual port
RAM mapping : the command area, the report area, the status area, the optional status area, the data buffer area, the interrupt control area, the general I/O and Relay Output area.
VI.1.1 - Mapping
VI.1.1.1 - Command AreaThe command area is located from $00 to $04.
Address $00 holds the command byte COMSYS,
and the next four locations hold the parameters
COMPAR[0..3]. The command parameters must be
entered before the command word is issued. Once
the command has been entered, the command byte
is reset and an acknowledge report is issued. A new
command should not be issued before the acknow-
ledge counter COMACK is incremented.
VI.1.1.2 - Report AreaThe report area is located from address $05 to
address $07. Location $05 holds the acknowledge
counter COMACK. Each time a command is ac-
knowledged, the report bytes COMREP[0..1] (if
any) are written by the ST75C530/540 into loca-
tions $06 and $07, and the content of COMACK is cremented. This counter allows the
ST75C530/540 to accurately monitor the com-
mand processing.
VI.1.1.3 - Status AreaThe status area is located from address $08 to $0B.
The error status word SYSERR is located at address
$08. This error status word is updated each time an
error condition occurs. An optional interruption IT0
may additionally be triggered in the case of an error
condition. Locations $09 and $0A hold the general
status bytes STATUS[0..1]. The meaning of the bits
depends on the mode of operation, and is described
in Chapter VIII. The third byte at address $0B holds
the Quality Monitor byte STAQUA.
VI.1.1.4 - Optional Status AreaThe user can program (through the DOSR com-
mand) the four locations STAOPT[0..3] of the Op-
tional Status Area ($0C to $0F) for the real time
monitoring of four arbitrary memory locations.
VI.1.1.5 - Data Buffer AreaThe data area is made of four 8-byte buffers
(see Paragraph VI.1.3 “Host Interface Summary”).
Two are dedicated to transmission and the two
others to reception. Each of the four buffers is
attached to a status byte. the meaning of the status
byte depends on the selected format of transmis-
sion. Within each buffer, D0 represents the first bit
in time.
VI.1.1.6 - VOCODER Buffer Area
(VOCODER Mode)This area is made of a 18+2 byte buffer. This buffer
contains the VOCODER frame. The first 18 bytes
VOCDATA contain the coded frame and the other
2 bytes VOCCORR the Error corrections bit (only
valid in low bit rate mode).
In the Receive Mode (CODER) the ST75C530/540
codes the received samples and writes the corres-
ponding bytes in the buffer. If the low bit rate mode
is selected, the ST75C530/540 computes the Error
corrections 2 bytes and writes them in the buffer.
In t he Transmit Mode (DECODER) the
ST75C530/540 reads the 18 coded bytes decodes
them and sends the signal to the analog output. In
the low bit rate mode if the Error Correction is
enabled, prior the decoding, the ST75C530/540
reads the 2 Error Correction Bytes and, if any,
corrects the first 18 bytes.
A mechanism of flags to share the buffer access
between the ST75C530/540 and the host controller
is controlled by the VOCSTA byte : In CODER mode, when the ST75C530/540 has
finis-hed writing the VOCDATA and VOCCORR
bytes, it writes $14 in VOCSTA and generate an
Interrupt IT1. The host must read the Data buffer
then clear the VOCSTA byte.In DECODER mode, the host must feed the
VOCDATA and, optionaly, the VOCCORR bytes,
then write $14 (if low bit rate) or $12 (if ADPCM)
in VOCSTA. The ST75C530/540 will read the
VOCDATA and VOCCORR bytes, clear the
VOCSTA and generate an Interrupt IT1. A si-
lence frame can be generated, in either low bit
rate or ADPCM mode, by writing 00 in all the
VOCDATA buffer, including the Error Correction
Bytes VOCCORR.
ST75C530 - ST75C54021/84
VI.1.1.7 - Interrupt Control AreaThe interrupt area, that start after the address $40
controls the behaviour of the Interrupts mecha-
nism. Register ITSRCR defines the source of the
interrupt, the register ITMASK allows independent
enabling or disabling of any of the interrupt’s
source, registers ITREST0 to ITREST6 reset the
corresponding interrupt source.
These registers are not affected by a INIT command,
they are only reseted by a Hardware RESET signal.
VI.1.1.8 - General IO and Relay Output AreaA set of 5 registers is directly accessible by the
controller to program the General IO pins and
Relay Outputs (see Paragraph VI.1.3 “Host Inter-
face Summary”). Two registers IODIR0 and IO-
DIR1 define the type of the IO pin, either Input or
Output (0 = input, 1 = output), and two registers
IODATA0 and IODATA1 define the IO pin signals.
The fifth register defines the Relay output signals.
These registers are not affected by a INIT command,
they are only reseted by a Hardware RESET signal.
The general IO are setup as input after the power
up or an hardware RESET . The relay output are
open after power up or an hardware RESET.
VI.1.2 - InterruptionsThe ST75C530/540 can generate 7 interrupts for
the controller. The interrupt handling is made with
a set of registers located from $40 to $5F.
The interruptions generated by the ST75C530/540
come from several sources. Once the
ST75C530/540 raises an interrupt, a signal (SINTR)
is sent to the controller. The controller has then to
process the interrupt and clear it. The interrupt source
can be examined in the interrupt source register
ITSRCR located a $50. According to the ITSRCR
bits, the interrupt source can be determined. Then
writing a zero at one of the memory location $40 to
$46 (Reset Interrupt Register ITRES[0..6]) will re-
set the corresponding interrupt (and thus acknow-
ledge it). The source of the interrupt can be masked
globally or individually using the Interrupt Mast
register ITMASK located at $4F.
The interrupt sources are : IT0 : Error
This signifies that an error has occurred and the
error code is available in the error status byte
SYSERR. This byte can be selectively cleared by
the CSE command. IT1 : VOCODER Buffer
Each time the ST75C530/540 have coded a
frame (CODER Mode) or decoded a frame (DE-
CODER Mode) this interrupt is generated. IT2 : Tx Buffer
Each time the ST75530/C540 frees a data buffer,
this interrupt is generated. IT3 : Rx Buffer
Each time the ST75C530/540 has filled a data
buffer, this interrupt is generated. IT4 : Status Byte
This signifies that the status byte has changed
and must be checked by the controller. IT5 : Low Power Mode
The ST75C530/540 has been awakened from the
low power mode by a low level on the RING pin
or a dummy write issued by the host. IT6 : Command Acknowledge
This signifies that the ST75C530/540 has read
the last command entered by the host, incre-
mented the command counter COMACK, and is
ready for a new command.
Note : Interrupt registers are cleared after a Hard-
ware RESET. These registers are not affected by
a INIT Command.
VI - USER INTERFACE (continued)
ST75C530 - ST75C54022/84
Figure 15 : Functional Schematic
VI - USER INTERFACE (continued)
ST75C530 - ST75C54023/84
VI.1.3 - Host Interface SummaryCOMMAND AREA
REPORT AREA
STATUS AREA
DATA BUFFER AREA (FAX Modes and Data Modes)
VOCODER BUFFER AREA (Vocoder Mode)
INTERRUPT AREA
GENERAL IO AND RELAY
Note : Registers which address is higher or equal to $40 are not affected by a INIT Command or a Low Power wake-up. They are reseted
only by a Hardware RESET.
VI - USER INTERFACE (continued)
ST75C530 - ST75C54024/84
VI.2 - Command SetThe Command Set has the following attractive
features : user friendly with easy to remember mnemonics, possibility of straightforward expansion with new
commands to suit specific customer require-
ments, easy upgrade of existing software using previous
modem based SGS-THOMSON products.
The command set has been designed to provide the
necessary functional control on the ST75C530/540.
Each command is classified according to its syntax
and the presence/absence of parameters. In the
case of a parametric command, parameters must
first be written into the dual port RAM before the
command is issued. Acknowledge and error report
is issued for each command entered.
VI.2.1 - Command Set Summary
VI.2.1.1 - Operational Control Commands
INIT Initialize. Initialize the modem engine.
Set all parameters to their default values
and wait for commands of the control
processor. Non parametric command.
IDT Identify. Return the product identification
code. Non parametric command.
SLEEP Turn to low power mode, the
ST75C530/540 enters the low power
mode and stops its crystal oscillator to
reduce power consumption. In this mode
all the clocks are stopped and the dual
RAM is unreachable.
HSHK Handshake. Begins the handshake
sequence. The modem engine generates
all the sequences defined in the ITU-T
recommendations. A status report
indicates to the control processor the state
of the handshake. This command only
applies to modes where a handshake
sequence is defined. A CONF command
must have been issued prior to the use of
HSHK. Non parametric command.
STOP FAX Stop. Stop FAX Half-duplex
transmitter. Non parametric command.
RTRA Retrain. Begin a retrain sequence in
V.32bis/V.32 or V.22bis modes as
descr ibed in the ITU-T
recommendations (ST75C540 only).
SYNC FAX Synchronize. Start/Stop of FAX Half-
duplex receiver. Parametric command.
CSE Clear Status Error. Selectively clears the Error
status byte SYSERR. Parametric command.
SETGN Set Gain. This command sets the global
gain factor, which is used for the transmit
samples. Parametric command.
VI.2.1.2 - Data Communication Commands
XMIT Transmit Data. Start/stop the
transmission of data. After a XMIT
command, the ST75C530/540 sends the
data contained in its dual port RAM.
FORM Selects the Transmission Format. This
command configures the data interface
for both receiver and transmitter
according to the selected data format.
Parametric command (HDLC, UART or
synchronous).
VI.2.1.3 - Memory Handling Commands
MWI
MWLOMemory Write Indirect
Memory Write Low Word
Memory Write. This command is used to
write an arbitrary 16-bit value into the
writable memory location currently
specified by a parameter. Parametric
command.
MRI
MRLOMemory Read Indirect
Memory Read Low Word
Memory Read. This command allows the
controller to read any of the ERAM or
CROM (ST75C530/540 memory
spaces) location without interrupting the
processor. Parametric command.
Complex Read. This command allows
the controller to read at the same time
the real and imaginary part of a complex
value stored in a double ERAM or
CROM location. This feature is very
interesting for eye pattern software
control and for equalization monitoring.
This command insures that the real and
imaginary parts are sampled in the
memory at the same time (integrity).
Parametric command.
VI - USER INTERFACE (continued)
ST75C530 - ST75C54025/84
VI.2.1.4 - Configuration Control Commands
ASEL Select the Analog path option, like
Microphone input, Speaker attenuation.
Parametric command.
CONF Configure. This command configures the
modem engine for data transmission and
handshake procedures (if any) in any of
the supported modes. The transmission
parameters are set to their default values
and can be modified with the MODC
command. Parametric command.
MODC Modify Configuration. This command
allows modification of some of the
parameters which have been set up by
the CONF command. It can also be used
to alter the mode of operations (short
train). Parametric command.
DOSR Define Optional Status Report. This
command allows the modification of the
optional status report located in the status
area of the dual port RAM. One can thus
select a particular parameter to be
monitored during all modes of operation.
Parametric command.
DSIT Define Status Interrupt. This command
allows the programming of the status
word bit that will generate an Interrupt to
the controller. Parametric command.
VI.2.1.5 - Tone Generation Commands
TONE Select T one. Programs the tone generator(s)
for the desired default tone(s). Additional
mnemonics provide quick programming of
DTMF tones or other currently used tones.
Parametric command.
DEFT Define Tone. Progra ms the tone
generator(s) for arbitrary tone synthesis.
Parametric command.
TGEN Tone Generator Control. Enables or
disables the tone generator(s).
Parametric command.
VI.2.1.6 - Tone Detection Commands
TDRC Read Tone Detector Coefficient. Read
one Tone Detector Coefficient.
Parametric command.
TDWC Write Tone Detector Coefficient. Write
one Tone Detector Coefficient.
Parametric command.
TDRW Read Tone Detector Wiring. Read one
Tone Detector Wiring connection.
Parametric command.
TDWW Write Tone Detector Wiring. Write one
Tone Detector Wiring connection.
Parametric command.
TDZ Clear T one Detector Cell. Clear internal
variables of a Tone Detector Cell.
Parametric command.
VI.2.1.7 - Miscellaneous Commands
CALL Call a Subroutine. Call a subroutine with
one Parameter. Parametric command.
JSR Call a Low Level Subroutine. Call an
internal subroutine with one parameter.
Parametric command.
VI.3 - Command Set Short Form* ST75C540 only.
VI - USER INTERFACE (continued)
ST75C530 - ST75C54026/84
VI.4 - Status - Reports
VI.4.1 - StatusThe ST75C530/540 has a dedicated status report-
ing area located in its dual port RAM. This allow a
continuous monitoring of the status variables with-
out interrupting the ST75C530/540.
The first status byte gives the error status. Issuing
of an error status can also be flagged by a mask-
able interrupt for the controller. The signification of
the error codes are given in Chapter VIII.
The second and third status bytes give the general
status of the modem. These status include for
example the ITU-T circuit status and other items
described in Chapter VIII “STATUS DESCRIP-
TION”. These two status can generate, when a
change occurs, an interrupt to the controller ; each
bit of the two byte word can be masked inde-
pendently.
The forth byte gives in real time a measure of the
reception quality. This information may be used by the
controller to monitor the quality of the received bits.
Four other locations are dedicated for custom
status reporting. The controller can program the
ST75C530/540 for a real time monitoring of any of
its internal RAM location. High byte or low byte of
any word can thus be monitored.
VI.4.2 - ReportsThe ST75C530/540 features an acknowledge and
report facility. The acknowledge of a command is
monitored by a counter COMACK located in the
dual port RAM. Each time a command is read from
the command area, the ST75C530/540 will incre-
ment this counter. For instance, when a MR (Mem-
ory Read) command is issued, the data is first
written in the report area, and the counter is incre-
mented afterwards. This way of processing insures
data integrity and gives additional synchronization
between the controller and the data pump.
VI.5 - Data ExchangesThe ST75C530/540 accepts many kinds of data
exchange : the default mode uses the synchronous
parallel exchange. Other modes include HDLC
framing support and UART. Detailed description of
the Data Buffer Exchanges modes is available in
the paragraph X.
VI.5.1 - Synchronous Parallel ModeThe data exchanges are made through the dual
port RAM and are byte synchronous oriented. The
double buffer facilities of the ST75C530/540 allow
an efficient buffering of the data.
VI.5.1.1 - TransmitThe controller must first fill at least the first buffer
of data (Tx Buffer 0) with the bits to be transmitted.
In order to perform this operation, the controller
must first check the Tx Buffer 0 status word
DTTBS0. If this buffer is empty, the controller fills
the data buffer locations (up to 64 bits), and then
writes in DTTBS0 the number of bytes contained in
the buffer. The controller can then either proceed
with the second buffer or initiate the transmission
with a XMIT command.
The ST75C530/540 copies the contents of the data
buffer and then clears the buffer status word in
order to make it again available, then generates an
IT2 interrupt. The number of bytes specified by the
status word is then queued for transmission. The
process goes on with the two buffers until an XMIT
command stops the transmission. After the finish-
ing XMIT command has been issued, the last buff-
ers are emptied by the ST75C530/540.
Errors occur when both buffers are empty while the
transmit bit queue is also empty. Error is signalled
with an IT0 interruption to the controller.
VI.5.1.2 - ReceiveThe controller should take care of releasing the Rx
buffers before the Data Carrier Detect goes true.
This is made by writing zero in the Rx Buffer Status and 1. The ST75C530/540 then fills the first
buffer, and once filled sets the status word with the
number of bytes received and then generates an
IT3 interrupt. It then takes control of the second
buffer and operates the same way. The controller
must check the status of the buffers and empty
them. Once the data read, the controller must
release the used buffer and wait for the next buffer
to be filled.
Error occurs when both buffers are declared full,
and incoming bits continue to arrive from the line.
Error is signaled by an IT0 interrupt.
VI.5.2 - HDLC Parallel ModeThis mode implements part of the High Level Data
Link Control formats and procedures. It is well
suited for error correcting protocols like ECM or
FAX T4/T30 recommendations. It supports the flag-
ging generation, 16-bit Frame Check Sequence, as
well as the Zero insertion/deletion mechanism.
VI.5.3 - UART Parallel ModeThis mode implement a 7 or 8 bit data format, it is
well suited for Caller ID or Minitel applications.
VI - USER INTERFACE (continued)
ST75C530 - ST75C54027/84
VII - COMMAND SET DESCRIPTIONCommands are presented according to the following form :
COMMAND Command Name Meaning COMMAND
Opcode Hexadecimal digit
Synopsis Short description of the functions performed by the command.
ParametersField Name of the addressed bit field.
Byte Index (or address in the dual port RAM) of the parameter byte (from 1 to 4).
Pos. Bit field position inside the parameter byte. Can either be a single position (from 0 to 7, 0
being LSB) or a range.
Value Possible values for the bit (resp. bit field). Range means all values are allowed. A star means a default
value. Values are expressed either under the form of a bit string, or under hexadecimal format.
ASEL ASEL
Opcode: 0B
Synopsis Select the analog path options. This command select the Attenuation/Mute of the outputs
TxA1/TxA2 and SPK1/SPK2/SPK3. This command select also the source of the Mic signal
MIC1/MIC2/MIC2 and the source of the Line Signal RxA/MIC3.
Parameters
CALL Call a Subroutine CALL
Opcode: 19
Synopsis CALL allows to execute a part of the ST75C530/540 firmware with a specific argument.
ParametersThis instruction can be used with SGS-THOMSON Microelectronics Application Laboratory Support for
special applications development or debugging needs. Contact your local representative.
ST75C530 - ST75C54028/84
CONF Configure for Operations CONF
Opcode : 20
Synopsis CONF allows the complete definition of the ST75C530/540 operation, including the mode of
operation (Tone, FAX Transmit, Voice Transmit, Voice Receive, DTMF Receiver, ...) and the
Modem or Vocoder Parameters (Standard, speed, ...). According with the 4 first bits of the
CONF Parameter the ST75C530/540 is put into the following mode of operation.
Notes : 1.This mode includes V.23/Bell202 FSK Demodulator and UART.
2.This primary Tone Detectors allows Detection of signal up to 3.3kHz. (Sampling Rate 7.2kHz).
3.This secondary Tone Detectors allows Detection of signal up to 1.8kHz (with Sampling Rate 4.8kHz) or up to 3.3kHz (with Sampling Rate 9.6kHz).
4.The DTMF detector and Call Progress Tone detector (CPT) are available only for V.21 Channel 2.
5.STA_CPT0, STA_CPT1 and STA_CPT10 in STATUS0.
6.STA_CCITT and STA_AT in STATUS1.
7.Not available in V.32bis/V.32.
VII - COMMAND SET DESCRIPTION (continued)
ST75C530 - ST75C54029/84
Parameters When the CONF_OPER is set to F, selecting the Modem Mode of operation, the parameters
have the following meaning :
Notes : 8. With conf 80 00 00 00 the coefficients of secondary tone detectors are not initialized. ST75C540 only.
10. V.22bis, V.22, V.32bis and V.32 modes ST75C540 only.
VII - COMMAND SET DESCRIPTION (continued)
ST75C530 - ST75C54030/84
Parameters CODER and DECODER ModesIn the VOCODER Modes, either CODER or DECODER, (CONF_OPER equals 2 or 8) the
parameters have the following meaning :
Parameters ROOM-MONITOR ModeIn the ROOM MONITOR Mode (CONF_OPER equals 9) the parameters have the following
meaning :
Parameters HANDSET/HANDSFREE ModeIn the HANDSET/HANDSFREE mode (CONF_OPER equals C), the parameters have the
following meaning :
VII - COMMAND SET DESCRIPTION (continued)
ST75C530 - ST75C54031/84
Complex Read CROpcode: 11
Synopsis CR allows the reading of a complex parameter. The parameter specifies the parameter address (for
the real part : the imaginary part is next location). CR returns the high byte value of both real and
imaginary part of the addressed complex parameter (see Chapter VIII “ST ATUS DESCRIPTION”).
Parameters
CSE Clear Error Status CSE
Opcode: 08
Synopsis CSE is used to clear the ST75C530/540 error status SYSERR byte. It is also used as an
acknowledge to the error condition handler.
Parameters
DEFT Define Arbitrary Tone DEFT
Opcode: 0E
Synopsis DEFT programs one of the four tone generator for arbitrary tone generation. The parameter
is the frequency of the generated tone expressed in Hertz between 0 and 3600Hz.
Parameters
DOSR Define Optional Status Report DOSR
Opcode: 0A
Synopsis DOSR specifies the address of the RAM variables to be monitored in the 4 locations
STAOPT[0..3] of the dual port RAM. It also specifies the assignment within the 4 locations.
Parameters
VII - COMMAND SET DESCRIPTION (continued)
ST75C530 - ST75C54032/84
DSIT Define Status Interrupt DSIT
Opcode: 13
Synopsis DSIT specifies the bit mask used with the STATUS[0] and STATUS[1] byte to generate an
interrupt IT4 to controller. Each time a bit change happens in the status words, assuming
the corresponding bit mask will be set, an interrupt will be generated.
Parameters
Note : The default IT Status is 0x3F for STATUS[0] and 0xFF for STATUS[1].
FORM Select Transmission Format FORM
Opcode: 09
Synopsis FORM defines the type of transmission used on the line.
Parameters
Note : 1. Valid only when transmitting.
HSHK Handshake HSHK
Opcode: 04
Synopsis HSHK is used to command the ST75C530/540 to begin the transmit handshake sequence
processing. The progress of the handshake is reported to the control processor.
Parameter Non parametric command.
VII - COMMAND SET DESCRIPTION (continued)
ST75C530 - ST75C54033/84
IDT Identify IDT
Opcode: 14
Synopsis IDT Return the ST75C530/540 Hardware and Software release number. See paragraph VIII.1.4.
Parameter Non parametric command.
INIT Initialization INIT
Opcode: 06
Synopsis INIT forces the ST75C530/540 to reset all parameters to their default conditions and restart
operations.
Parameter Non parametric command.
Note : This command makes a software reset of the ST75C530/540 and so cannot have the regular handshake protocol. It
does not increment the COMACK, neither generate an Interrupt.
JSR Call a Low Level Subroutine JSR
Opcode: 18
Synopsis JSR allows to execute a part of the ST75C530/540 firmware with a specific argument.
ParametersThis instruction can be used with SGS-THOMSON Microelectronics Application Laboratory Support for
special applications development or debugging needs. Contact your local representative.
VII - COMMAND SET DESCRIPTION (continued)
ST75C530 - ST75C54034/84
MODC Modify Configuration MODC
Opcode: 21
Synopsis MODC allows the modification of the parameters defined by the CONF command.
Parameters
Notes : 1. In the modes where they are active. Short train sequence must be preceded by at least one successful long train sequence at the same data rate. For
V.17 a successful long train at any data rate must preceded the short train. Only coder or decoder can be enabled at the same time. Only when sending V.17, V.33, V.29 or V.27ter. French Minitel Application (TVR : Teletel Vitesse Rapide). ST75C540 only
VII - COMMAND SET DESCRIPTION (continued)
ST75C530 - ST75C54035/84
Memory Read MROpcode: 10
Synopsis MR allows the reading of a 16-bit parameter. The parameter specifies the parameter address.
Parameters
MRI Memory Read Indirect MRI
Opcode: 28
Synopsis MRI allows the reading of a 16-bit parameter. The parameter specifies an indirect address.
Refer to the “RAM Mapping Application Note” (delivered on request according to revision
number). The advantage to use MRI instead of MR is that the Indirect Address is constant
over the different release of the product.
Parameters
MRLO Memory Read Low Word MRLO
Opcode: 29
Synopsis MRLO allows the reading of the memory location which address coresponds to the previous
MR or MRI Absolute Adress minus 1. This command must be preceded by a MR or MRI
command. This command does not have any parameter. The double word reading is
executed by the MR or MRI previous command.
Memory Write MW
Opcode: 12
Synopsis MW allows the writing of a 16-bit parameter. The parameter specifies the address as well
as the value to be transferred.
Parameters
VII - COMMAND SET DESCRIPTION (continued)
ST75C530 - ST75C54036/84
MWI Memory Write Indirect MWI
Opcode: 2A
Synopsis MWI allows the writing of a 16-bit parameter. The parameters specifies an indirect address as well
as the value to be transferred. Refer to the “RAM Mapping Application Note” (delivered on request
according to revision number). The advantage to use MWI instead of MW is that the Indirect Address
is constant over the different release of the product.
Parameters
MWLO Memory Write Low Word MWLO
Opcode: 2B
Synopsis MWLO allows the writing of a 16-bit parameter at the address defined by the following MW
or MW Absolute Address minus 1. This command must be followed by a MW or MWI
command.The double word writing is executed by the MW or MWI following command.
Parameters
RTRA (ST75C540 only) Retrain RTRA
Opcode: 02A
Synopsis RTRA is used to force the ST75C530/540 to initiate a retrain sequence or a rate negotiation.
If MODC_NOQUA bit is set, the ST75C530/540 will initiate a transmission at the maximum
speed defined by the RTRA parameter, otherwise it will found the best reliable speed based
on the quality of the line (within the RTRA allowed speed).
Parameters
VII - COMMAND SET DESCRIPTION (continued)
ST75C530 - ST75C54037/84
SETGN Set Output Gain SETGN
Opcode: 02
Synopsis SETGN is a command which sets the scaling factor of the transmit samples. It is used for
setting the output level or for setting the level of the tone generators. The gain value is given
in the form of a 2’s complement 16-bit value.
ParameterExample
The multiplication factor is : 10 (-1/20) = 0.89125 for 1dB step.
SLEEP Turn to Sleep Mode SLEEP
Opcode: 03
Synopsis SLEEP is used to force the ST75C530/540 to turn to low power mode.
Parameter Non parametric command.
Note : When receiving this command the ST75C530/540 will stop processing and so cannot have the regular handshake protocol.
It does not increment the COMACK, neither generate an Interrupt.
STOP FAX Stop Transmitter STOP
Opcode: 25
Synopsis STOP is used, in FAX Modes, to force the ST75C530/540 to turn off the transmitter in
accordance with the corresponding ITU-T V.33/V.17/V.29/V.27 recommendation.
Parameter Non parametric command.
Note : When receiving this command the ST75C530/540 will stop sending regular Data. This command must be preceded by a
XMIT Stop command. The ST75C530/540 will wait until all the transmit buffers are sent before starting the Stop sequence.
SYNC FAX Synchronize the Receiver SYNC
Opcode: 26
Synopsis SYNC is used, in FAX Modes, to force the ST75C530/540 to Start/Stop the receiver in
accordance with the corresponding ITU-T V.33/V.17/V.29/V.27 recommendation.As soon as
the ST75C530/540 receives the SYNC Start command it sets its receiver to detect the FAX
synchronization signal.This command is the equivalent HSHK command for the receiver.
Parameters
VII - COMMAND SET DESCRIPTION (continued)
ST75C530 - ST75C54038/84
TDRC Tone Detector Read Coefficient TDRC
Opcode: 1A
Synopsis TDRC Read one Coefficient of the selected Tone Detector Cell.
ParametersThe command answer is : Low Byte of Coefficient followed by High Byte of Coefficient.
Note 1 : Value 30 and 40 of byte 2 are available only for secondary tone detector.
TDRW Tone Detector Read Wiring TDRW
Opcode: 1B
Synopsis TDRW Read Wiring of the selected Tone Detector Cell.
ParametersFor primary tone detector
The command answer is :
a) If TD_W_ADDR = 0 : - First Byte is the Node Number of the Signal connected to Biquadratic Filter input.
- Second Byte is the Node Number of the Signal connected to the Energy estimator input.
b) if TD_W_ADDR = 1 : - First Byte is the Node Number of the Signal connected to Comparator Negative input.
- Second Byte is the Node Number of the Signal connected to the Comparator Positive input.
For secondary tone detector TD_W_ADDR is not defined. First byte is 00 if relative comparison is not mandatory,
First byte is 01 if relative comparison is mandatory. Second byte is for the configuration of the secondary tone detector :
C0 configuration 1+1 of secondary tone detectors,
E0 configuration 1+1+2,
F0 configuration 1+1+1.
VII - COMMAND SET DESCRIPTION (continued)
ST75C530 - ST75C54039/84
TDWC Tone Detector Write Coefficient TDWC
Opcode: 1C
Synopsis TDWC Write one Coefficient of the selected Tone Detector Cell.
Parameters
Note 1 : Value 30 and 40 of byte 2 are available only for secondary tone detector.
TDWW Tone Detector Write Wiring TDWW
Opcode: 1D
Synopsis TDWW Write Wiring of the selected Tone Detector Cell.
Parameters
For Primary Tone DetectorIf TD_W_ADDR = 0 (Select Biquad and Energy Inputs)
If TD_W_ADDR = 1 (Select Comparator Inputs)
For Secondary Tone Detector
VII - COMMAND SET DESCRIPTION (continued)
ST75C530 - ST75C54040/84
TDZ Tone Detector Clear Cell TDZ
Opcode: 1E
Synopsis TDZ Clears all internal variables of one T one detector cell including Filter local variables and
energy estimator. This command must be sent after changing coefficients of a cell to avoid
instability.
Parameters
TGEN Enable/Disable Tone Generators TGEN
Opcode: 0D
Synopsis Enable or disable one of the four tone generator, define the output of the tone generator
either Line or Audio.
Parameters
VII - COMMAND SET DESCRIPTION (continued)
ST75C530 - ST75C54041/84
TONE Predefined Tones TONE
Opcode: 0C
Synopsis TONE programs the tone generator for the predifined tones. The tone generator #0 and
eventualy #1 are reprogrammed with this command. The tone generator #0 and eventualy
the #1 are enabled. Using a value not in the following table will disable tone generator #0
and #1.
Parameters
XMIT Start/stop Transmission XMIT
Opcode: 01
Synopsis XMIT start or stop the transmission of the Transmit Data.
Parameters
VII - COMMAND SET DESCRIPTION (continued)
ST75C530 - ST75C54042/84
