M494B1 Fast Delivery |IC PHOENIX CO.,LIMITED

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M494B1
SINGLE-CHIP VOLTAGE TUNING SYSTEM WITH 4 ANALOG CONTROLS AND mP INTERFACE
M494
SINGLE-CHIP VOLTAGE TUNING SYSTEM WITH ANALOG CONTROLS AND μP INTERFACE
June 1991
DIP40
(Plastic Package)
ORDER CODE: M494B1 NON-VOLATILE MEMORY FOR 20 PRO-
GRAM WORDS (17 BITx 20) TUNING VOLTAGE12 BITS BAND2 BITS MULTI STANDARD2 BITS PROGRAM SKIP BIT1 BIT 10,000 MODIFY CYCLES PER WORD MIN.10 YEARSDATARETENTION.13 BITVOLTAGESYNTHESIZER(BRM+ PWM). NV MEMORY FOR4 ANALOG CONTROLS BITx4).4 BAND SWITCH OUTPUTS
(VHFI&III, UHF, CATV).5x7 KEYBOARD.2 AUDIO VISUAL OUTPUTS (VCR& PC).2 CODED MULTI STANDARD OUTPUTS
(e.g. PAL, SECAM, NTSC etc.). DIRECT 11/2 DIGIT7 SEGMENT COMMON
ANODE LED DISPLAY DRIVING. PCM REMOTE CONTROL RECEIVER
(M708 transmitter). 5-BIT DATA INPUT+ CONTROL LINE FOR INTERFACE. LINEAR AFC DEFEAT OUTPUT. FLYBACK/SYNC. COINCIDENCE INPUT FOR
SEMI-AUTOMATIC SEARCH. STANDBY OUTPUT. OPTION SELECT:16 OR20 PROGRAMS. POWER UP MODE. PROGRAM SKIP DEFEAT. AV OPTIONS.1* OR DECADE MODE OPTIONIN 20 PRO-
GRAM OPTION. TEMPORARY ANALOG UP/DOWN INDICA-
TOR ON LED DISPLAY. BAND SKIP OPTION. 455TO 510kHzCHEAP CERAMIC RESONATOR. VDD =5V± 5%. VPP= 25V± 1V
DESCRIPTION
The M494isa monolithic LSI integrated circuit
fabricatedin SGS-THOMSON’sEPM2process;an
N-channel, Planox, double poly MOS process ca-
pableof includinga floating gate NV memory cell
(EEPROM).
The i.c. has been designedasa complete digital tuning system based on the voltage synthesis
principle andasa replacementforall the conven-
tional potentiometers and band switches particu-
larlyin low cost TV sets.It also provides some
functionsnormally only associated with higher cost
sets. NV memoryis integratedon the chip together
with allthe necessarycontrol circuitryto providethe
program memory. Separate NV memoryis also
integratedto provide the memory for four analog
controls.A seven segment LED display can be
directly drivenby the chipto display the program
selected, and the directionof movementof the
analog controls. Provisionis made fora remote
control receiver both on andoff chip, the latteris
interfaced viaa data input and single control line.
(Thisenablescontrolbya microprocessor).A local
keyboard canbe used with the deviceina variety configurations.An option select pin providesfor
different program number options, power up op-
tions and skip associated functions. This deviceis
anothersignificant step towards the complete inte-
grationof TV control circuitry.
The deviceis packagedina 40 pin DIL plastic
package.
1/22
OPTIONSELECT
DISPLAY DRIVEi
AV0
AV1
MEMORYTIMING
VPP
VSS
VDD
UHF
CATV
VHF1
VHF3
OSC.OUT
OSC.IN
TUNING
CONTRAST
MS0
MS1
BRIGHTNESS
TEST1
DATA HANDSHAKE
STANDBY
AFCDEFEAT
FB/SYNC COINCIDENCE
REMOTECONTROL
VOLUME
SATURATION
494-01.EPS
PIN CONNECTIONS
ABSOLUTE MAXIMUM RATINGS
Symbol Parameter Value Unit
VDD Supply Voltage –0.3to7 V
VPP Memory Supply Voltage –0.3to26 V Input Voltage –0.3to15 V
VO(off) Off State Input Voltage 15 V
IOL Output Low Current
LED Driver Outputs: pina-g
pinh+i
All other Outputs
tPD Max. Delay between Memory Timing& Memory Supply Pulses 5 μs
Ptot Total Package Power Dissipation 1 W
Tstg Storage Temperature –25to+ 125 °C
Top Operating Temperature 0to+70 °C
Cos Capacitanceon Option Select Pin 100 pF
Ros Resistanceon Option SelectPin 1 kΩ
Cdk Capacitanceon data outputs& keyboard inputs when lines are
connectedbya keyboard switch closure
150 pF Series Resistanceof Single Keyboard Switch 10 kΩ
Crts Capacitanceon Data HandshakePin 50 pF
Stresses above those under ”Absolute Maximum Ratings” may causes permanent damagetothe device. Thisisa stress rating onlyand
functionaloperationofthe deviceat theseorany other conditionsabove those indicatedinthe operational sectionsofthis specificationisnot
implied. Exposureto absolute maximum rating conditionsfor extended periodsmay affect device reliability.
494-01.TBL
M494
2/22
STATIC ELECTRICAL CHARACTERISTICS (Tamb =0to 70°C, VDD=5V unless otherwisespecified)
Pins Symbol Parameter Test Conditions Min. Typ. Max. Unit
Memory Supply IPP Memory Supply
Current
VPP= 25V Write Peak
Write Average
Erase Peak
Erase Average
Read Peak
Read Average
2.5 Pull Down 25 kΩ
Memory Timing VOL VDD= 4.75V,IOL= 2.5mA 8 V
IO(off) Leakage VDD= 4.75V,VO= 26V 100 μA
Tuning VOL VDD= 4.75V,IOL= 5mA 1 V
VDD IDD Supply Current VDD= 5.25V 100 mA VI pktopk 0.5 13.2 V
FB/sync. Coin. Input VIL 0.8 V
VIH 2.0 V
IIL VDD= 5.25V,VIL= 0.8V –0.4 mA Pullup 30 kΩ
Vol. Brigh. Sat.
Contr. DACs
VOL VDD= 4.75V,IOL= 4mA 1 V
IO(off) VDD= 5.25V,VO= 13.2V 50 μAi VIL 1.5 V
VIH 3.5 V
IIL VDD= 5.25V,VIL= 1.5V –50 μA Pullup 200 kΩ
VOH VDD= 4.75V,IOL= 30mA 1.5 V
D0, D1
D2, D3
VIL 1.5 V
VIH 3.5 V
IIL VDD= 5.25V,VIL= 1.5V –0.4 mA
VOL VDD= 4.75V,IOL= 1mA 0.4 V
IO(off) VO(off)= 5.5V 25 μA Pullup 30 KΩ
MS0, MS1 AFC
def. AV0, AV1
VOL VDD= 4.75V,IOL= 1mA 0.4 V
IO(off) VDD= 5.25V,VO 13.2V 50 μA
Option Select VIL 1.5 V
VIH 3.5 V
IIL VDD= 5.25V,VIL= 1.5V –0.4 mA Pullup 30 kΩ
Standby VOL VDD= 4.75V,IOL= 100μA 0.4 V VDD= 4.75V,VO= 0.7V 1.6 mAb,c,d,e,f,g VIL 1.5 V
VIH 3.5 V
IIL VDD= 5.25V,VIL= 1.5V –50 μA Pullup 200 kΩ
VOL VDD= 4.75V,IOL= 15mA 1.5 V
Display Drive VOL VDD= 4.75V,IOL= 5mA 0.4 V
IO(off) VDD= 5.25V,VO= 13.2V 50 μA
UHF,III,I, CATV VOL VDD= 4.75V,IOL= 1mA 3 V
VOH VDD= 4.75V,IOH=– 150μA 2.4 V
VIL 1.5 V
VIH 3.5 V
IO(off) VDD= 5.25V,VO= 13.2V 50 μA
Data
Handshake
VOL VDD= 4.75V,IOL= 1mA 3 V
VOH VDD= 4.75V,IOH= 150μA 2.4 V
VIL 1.5 V
VIH 3.5 V
IIL VDD= 5.25V,VIL= 1.5V –0.4 mA Pullup 30 kΩ
IO(off) VDD= 5.25V,VO= 13.2V 50 μA
494-02.TBL
M494
3/22
DEFINITION OF TERMS
The M494 has four conditionsor states thatit canin which are defined below. Logic LO 0V and
logicHI= 5V.
Powered Down
VDD =0V. VPP =0V
VDD =5V. VPP= 25V.
Device driving display normally.
Data Handshake pinconfiguredas RTS i/p.
Standby o/p= HI. All other functions operating
normally.
Standby
VDD =5V. VPP =0V.
Device driving displayto showa single static bar segment).
Data Handshake pin configured asRTS i/p.Stanby
o/p= LO.
All keyboard commands are disabled except any
program command On/Off, On/Stanby.
Memory sequenceupor down,1* and ±10 (dec-
ade) commands.
Analog controls. Tuning, AV, MS and AFC defeat
o/p’s= LO. Band o/p’s=HI (externally pulled up).
See Standby section for more detail.
Off
VDD =5V. VPP= 0V. Device not driving display.
Data Handshakepin configuredas OFF o/p.
Standby o/p= LO. Display disabled and Display
drive o/p=HI (externally pulled up).
All keyboard commands disabled except ON/OFF.
Remote and data command sources disabled.
Analog controls, Tuning, AV, MS and AFC defeat
o/p’s=HI (externally pulled up).
FUNCTIONAL DESCRIPTION (clock frequency= 500kHz)
VDD &VSS
VDD =+5V± 5%. When applied,an internal power resetof 110msis generated.Thevoltagethresh-
old for the resetisin the range3to 3.5V butisin
fact the pointat which the internal clock phases
start.
VSS= 0V. This pinis connectedto the substrateof
the i.c. andis the reference forall parametersof
the device.
Oscillator I/O
The frequencyof the oscillator shouldbe between
445 and 510kHzusinga cheap ceramic resonator.
The reference frequencyof the remote control
transmitter must also bein the same range i.e.if
the oscillator frequencyis 455kHz then the trans-
mitter frequency couldbe 510kHzor vice versa.
Test
This pinis normally used forpost fabrication testing
purposes only and shouldbe tiedto VSS. However
this pin can be usedby SGS-THOMSONor the
OEMto enable external loadingof the memory.
Detailsof howto achieve this canbe furnishedby
SGS-THOMSON.
Remote Control Input
The integratedRC receiver decodessignals trans-
mitted by the M708 (address 10). The minimum
signal amplitude should be 0.5V peakto peakat
the input pin. The minimum pulse width shouldbe
8μs.
The signal from the preamplifier (TDA8160)is
broughtto the RC signal input viaan AC coupling
network (see Figure1).
VDD (TDA8160) R C 2.2kΩ 4.7nF
12V 10kΩ 4.7nF
TDA8160
M494
494-02.EPS
Figure1
The inputis self biasedto approx. 1.5V. Whena
large signalis appliedto the inputa level shift will
take place predominantly dueto the coupling net-
work.
However another time constantis also visible due the couplingC and the internal resistorRi. (see
Figures.2& 3).
Remote
ControlI/P Cct1.5V
494-03.EPS
Figure2
M494
4/22
1 =RC2 =Ri.C1.5V
494-04.EPS
Figure3
FUNCTIONAL DESCRIPTION (continued)
Several tests are performedon the signal: Measurementof the pulse distanceT (time
base synchronization). Checkof thebit positions relativeto the time
base windows. Checkof the parity bit. Checkof theabsenceof pulses between parity
and stop pulses. Checkof the noise level. The receiver checks
the noise level fora timeT after each pulse
detected.all these tests are successful the received word stored and decoded.If notitis rejected. The
transmissionis terminatedon receptionof the end transmission (EOT) codeorif the internal timer
measuresa transmission interruptionof morethan
550ms. For more detail concerning the operation the RC receiver referto SGS-THOMSON Tech-
nical Note No. 155 pp11-12.
The RC receiver and the local keyboard have the
same command source priority i.e.a local com-
mandis not accepted untila previously accepted command has been completely executed and
the EOTcode transmitted. Similarlyifa localcom-
mandis under execution thenan RCcommand will
not be accepted. The RC truth table and com-
mands are shownon the next page.
Analog Control Outputs
Four analog control outputs are implementedto
provide for Volume, Brightness, Saturation and
Contrast from four6bit D/A’s. These D/A’s use the
Pulse Width Modulation techniqueto synthesizea
pulse trainof constantfrequency but variablepulse
width (PWM). Each output deliversa 7.8kHz
square wave whose duty cycleis variablein 63
steps. External RC filtering and level shiftingis
requiredto realisea static DC voltage from the
pulse train.If the analog outputs are continuously
varied by command from the keyboardor data
command sources the outputs will change approx.
every 112ms (fck= 500kHz)or approx. every
102msif the commandis issued from the RC
command source. One analog controlis specifi-
cally designedasa volume controlas mute circuitry builtin. startup reset the analog control outputs except
volume are enabled aftera periodof approx.
1.1 seconds.In the Standby and Off statesall the
analog control outputs are pulledto logic LO.
The normalise command reads the contentsof
each analog memory sequentiallyto its corre-
sponding counter and D/A output.
Tuning Output
The tuning voltageis generated froma 13 bit
counter.The programmemory stores the12 MSB’s the tuning word. The rangeof the AFC circuitryat least3 bitsso the LSBof the tuning counter
does not affect the resolutionof tuning.
The contentsof the counter are converted usinga
PWM anda Bit Rate Multiplier (BRM) technique. bits gives 8192 steps which yieldsa resolution approximately 3.9mV witha max. tuning voltage 32V. This correspondstoa resolutionof about
75kHzin the UHF band. The5 MSB’sof the tuning
word are converted using PWM and the remaining bits using BRM. Thus as the tuning word in-
creases fromall zeroes thenumberof pulsesinone
period increasesto 256 withall the pulses being
the same length(to =2μs). For values larger then
256 PWM conversion takes place where the num-
berof pulsesin one period stays constantat 256
but the width changes.
Whenthe pulse width reaches 15to two successive
pulses ”link” together and the numberof pulses
decreases (see Figure4).
The pulse trainis fedtoan external low pass filter realisea DC voltage. The temperaturedepend-
enceof this systemis predominantly the switching
timesof the output pulses andas there are onlya
maximumof 256 pulsesin one periodthe tempera-
ture stabilityis very good.
InStandby and Off statesthe tuningoutputis pulled logic LO.
256OF PULSES
TUNING
VOLTAGE1V 31V
494-05.EPS
Figure4
M494
5/22
FUNCTIONAL DESCRIPTION (continued)
Table1: Remote Control Commands (address 10, code= 1010)
Command
Number
Function Code Programs 20 Programs C1 C2 C3 C4 C5 C6
EOT
Standby
Mute (toggle)
Program1
Program2
Program3
Program4
EOT
Standby
Mute (toggle)
Program1
Program2
Program3
Program4
Contrastup
Contrast down
Program5
Program6
Program7
Program8
Contrastup
Contrast down
Program5
Program6
Program7
Program8
Memory Seq.up
Memory Seq. down
Program9
Program10
Program11
Program12
Memory Seq.up
Memory Seq. down
Program9
Program010 (decade)10 (decade)
Normalise
On/stby (tog.)
Program13
Program14
Program15
Program16
Normalise
On/stby (tog.)
NOP
NOP
NOP
Volumeup
Volume down
Brightnessup
Brightness down
Saturationup
Saturation down
Volumeup
Volume down
Brightnessup
Brightness down
Saturationup
Saturation down
The above table shownsthe difference betweenthe16and20 programoptions with respecttothe remote control commands. Commands16,
17,18 &21 change functionbetweenthetwo options. Commands22,23&24 shouldnotbe usedinthe20 program option,as they haveno
function.
NOP=No operation
Program Memory memory(EEPROM)is integratedon the chipto
provide storageforupto20 stations.
Each memory locationis17 bitsin lengthproviding bitsfor tuning voltage,2 bitsfor band,2 bitsfor
two coded multi-standard outputs and1 bit pro-
gram skip flag.
Individual program words canbe read oncommand
from the keyboard, remote or data command
sources but can onlybe writtenon command from
the keyboard.
There are two methodsfor storinga program (writ-
ing the memory): pre and post tuning selectionof
the programnumber. See Commands, section7.
Reading each memory locationin sequence (upor
down) can alsobe achieved fromall the command
sources.
All memory timing functions are providedon chip
and only one external transistoris requiredto
switch the externalmemory supply (25V).
There are essentiallytwo operationscarried outon
the memory: Write/Modify and Read.
The Write/Modify cycle consistsof3 steps: All ”1s” are writtento thebitsof the addressed
word. All bitsof the word are erased. The new contents are written.
Usingthis method allthe bitsof theaddressed word
are aged the same. Formore detail concerningthe
write, erase and read current waveformsat the
Memory Supplypin see M491 datasheet.
Memory For Analog Controls
The memoryfor the analog controlsis electrically
identicalto the main programmemory butis organ-
isedas four 6-bit words locatedin two sequentially
addressed wordsat the memory. Each word cor-
respondsto the Volume, Brightness, Saturation
and Contrast outputs.At power on reset and nor-
malise command each memory wordis read outto
its corresponding counter and D/Ain sequence.
M494
6/22
DISPLAYSCAN DECISION
DISPLAY
DRIVE 640μs 2ms)
MUX PERIOD (8ms)
INITIALIZE
494-06.EPS
Figure5
FUNCTIONAL DESCRIPTION (continued)
Display, Keyboard and Data Multiplexing
Logicis integratedon the chipto provide the mul-
tiplexing between the display, keyboard and data
inputs.In the On state and with the Data Hand-
shake pinat logicHIas an input the display and
keyboard are muxed together.See Figure5. Each
column output goesto logic LOin sequence and
the row inputs are scannedfora key closure.In
chronological order across the total mux. period
thereis: initialisation, scan, decision and display
periods.
The Data Handshake pin hasa complex logical
function.It has two modesof operation:asa hand
shake I/O linetoa μP andasan output lineto theto signal that the M494isin the Off state.In order achieve this function careful signal timingis
required both internally and externallyto the chip.
See Figure6. When the deviceisin the OFF state
the Data Handshake pinis usedto signal this
conditionto theμPby being pulled LO. B1 C1 D1 A2 B2 C2 D2 A3
DATA DATA
O/II/OO/II/O (EOT= ENDOF
TRANSMISSION)
K/B ANDRCI/P
DISABLEDTILL
EOTEXECYTION
DATA
HANDSHAKE
D0-D4
EOE
(ENDOF TRANSMISSION)
NOT TOSCALE
DATA HANDSHAKE
PIN CONFIGURATIONRTS tCTSO/PHCRSj tHSCRO/PCTS
494-07.EPS
-494-03.TBL
Figure6: Data-input-timing Symbol Parameter Min. Typ. Max. Unit
1tRTS Requestto Send Pulse (RTS) 5 10 μs
2tCTS Clearto Send (CTS) 512 μs
3tO/P Pin Output Configuration 8 ms
4tHS Handshake Time 12 μs
5tS Data Setup Time 10 128 μs
6tH Data Hold Time 128 256 μs
7tJ Synchronization Jitter 8 ms
8tCR CTS tonext RTS Pulse 98 ms
Note: Oscillator Clock= 500kHz
M494
7/22
FUNCTIONAL DESCRIPTION (continued)
Display
The M494is capableof directly drivinga1 digit
common anode LED displayat the max. sink cur-
rentof 15mA per segment. The h+i pinis capable sinkinga max. currentof 30mAso that these two
segments canbe driven from the same pin andbe
the same brightnessas the other segments. instructionfrom the internal command decoder
the displayshows programme number, directionof
analog controlmovement, decade changeor Mem-
ory Addressingfunction active. Analog controlsin
this context are definedas Tuning, Volume, Con-
trast, Saturation& Brightness. The formatsof the
display foranalogcontrol direction, decadechange
and MemoryAddressing are shown below respec-
tively:
For the analog controls the above conditionis
displayed withan ”overrun” timeof 300ms. i.e. the
display will show the ”arrows” fora period of
300ms after the releaseof any analog controlup down key. The Memory Addressing function
display flashesat 5Hzafterthe Memory Addressing
functionis commanded and continuesto flash until programmeis selectedor any other commandis
given.In1* theg segment only flashesat 5Hzand
continuesto flash untila programme numberis
selected or any other commandis given.Ifin
Memory Addressing and1*is pressed then the
display aboveis shown with segmentsg&d only
flashingat 5Hz untila programme numberis se-
lectedor any other commandsis given. When
Storeor Set Skip Flag commands are executedthe
whole displayis flashedat 5Hzfor1 second.
Keyboardis possibleto implementa keyboard witha max.
sizeof35 keysasa5x7 array. Fig.8 shows the
arrangementof the key matrix. Each key connects row (a-g) witha column (D0-D4) witha max.
resistanceof 10kΩ. De-bounce logicis integrated the chip that only allows acceptanceofa com-
mandif the keyis closed for longer than 40ms
exceptfor the On/Standby and On/Off commands
where therelevant keys mustbe closed forapproxi-
mately 100ms. Thisis equivalentto2 received RC
commands). DOWN MEMORY
ADDRESSING I* AND
MEM.ADDR.
494-08.EPS
For the main keyboard matrix (a-gx D0-D4),if the
logic detects two keys closed simultaneously the
displayis blankedto indicate this conditionto the
user andno commandis executed.When the logic
detects only one key pressed the display will re-il-
luminate and the commandbe executed.
This avoidsconfusionasto which command should executed and provides feed backto the user.
For the Option select lineall options/commands
canbe active simultaneously.* modeor decade mode canbe selectedon the
option select lineby the presenceofa diodeor not
respectively. These two modes are only activefor
the20 program option and are described below:1* mode the display will togglein& outof the
conditionshownin the Display Section. Accessto
programsin the first decadeis made by simply
pressing any 0-9 program key and accessto pro-
gramsin the second decade, whatever the current
programis madeby pressing1* followedby any
0-9 program key. decade modeon pressing either ±10 (decade)
keys the display will lightor extinguish the half digit
respectively and simultaneously effect the tuning
information.e.g.if the deviceisin program3 press-
ing+10 (decade)keywill give program 13and then
pressing- 10 (decade) key will give program3.
Pressing- 10 (decade)again will haveno effect.
The20 program option select acts likean enable
for the1*or decade modes. i.e. the1*or decade
modes are only selectablein the 20 program op-
tion.In16 program option the functionof the1*
key, program key0, -10 (decade)&+10 (decade)
are changedtono function, programme 10, 11& respectively. i.e. The difference between fig.78 for those keys that change function. the1* keyis pressed followedby brightnessup
for example the device will increase the brightness
only and reset the1* command i.e. the last
command from any command source will al-
ways be executedifitisa single keystroke
command and the1* command will beresetby
it.Itis possibleto press the1* keyonthe keyboard
and thena program 0-9command from RC orData
command sourcesor vice versa. Thus there are2
methodsof selectinga program from the keyboard
for the16 program option: direct access (onlyup 12 programs)or Memory sequence up/down.
And there are3 methodsof selectinga program
from the keyboardfor the20 program option:1*
mode, decade mode and Memory sequence
up/down.
M494
8/22
FUNCTIONAL DESCRIPTION (continued)
M494
NORMALIZE CONTRAST
STORE
PROGRAM
ON/STANDBY
(TOGGLE)
CONTRAST
DOWN
STORE
ANALOG
VALUES
VOLUME
BRIGHTNESS
TUNE
VOLUME
DOWN
BRIGHTNESS
DOWN
TUNE
DOWN
SET SKIP
FLAG
ON/OFF
(TOGGLE)
BAND
SEQUENCE
SATURATION
MEMORY
SEQUENCE
SEQUENCE
MUTE
(TOGGLE)
SATURATION
DOWN
MEMORY
SEQUENCE
DOWN
MEMORY
ADDRESSING
P/U*
OFF
16* AV1*
OPTION
SELECT
AV2 P/U
STANDBY
SKIP OFFi= DEFAULT P/U= POWER UP
494-09.EPS
Figure7: Keyboard16 Programs
M494
9/22
FUNCTIONAL DESCRIPTION (continued)
M494
NORMALIZE CONTRAST
STORE
PROGRAM
ON/STANDBY
(TOGGLE)
CONTRAST
DOWN
STORE
ANALOG
VALUES
VOLUME
BRIGHTNESS
TUNE
VOLUME
DOWN
BRIGHTNESS
DOWN
TUNE
DOWN
SET SKIP
FLAG
ON/OFF
(TOGGLE)
BAND
SEQUENCE
SATURATION
MEMORY
SEQUENCE
SEQUENCE
MUTE
(TOGGLE)
SATURATION
DOWN
MEMORY
SEQUENCE
DOWN
MEMORY
ADDRESSING
P/U*
OFF
AV1*
OPTION
SELECT
AV2 P/U
STANDBY
SKIP OFFi
DECADE
+10
DECADE
DECADE*
MODE
1*MODE= DEFAULT P/U= POWERUP
494-10.EPS
Figure8: Keyboard20 Programs
M494
10/22
FUNCTIONAL DESCRIPTION (continued)
Data Input
Shown below are the codes for the commands:
see Table2.
The Data input will accept signals whose timingis
definedin Figure6 and electrical characteristics
definedin the tableof static electrical charac-
teristics. The EOT code mustbe transmitted after
each commandaftera min. periodof 112ms.
Band Outputs
Four band outputs are providedfor selectionof the
signal band: VHFI &III, UHF and CATV. Bandskip
logicis implementedso thatby tieing the relevant
pinto VSSa band canbe skippedin regionsof no
transmissionin that band. The bands can be se-
lected onlyina rolling sequenceby the band se-
quence keyboard command. The sequenceisas
follows: VHFIII, UHF, VHFI, CATV.
Multi Standard Outputs
Two coded multi standard outputs(or general pur-
pose TV system flags) are providedso that the TV
set canbe designedfor usein areasof more than
one transmission standard. This function requires external decoderto realise 4differentstandards
e.g. PAL1, PAL2, NTSC, SECAM etc. The multi
standard sequence command available from the
keyboard givesa simple binary countat the two
outputs: 00, 01, 10, 11,00 etc.In Standby and Off
states the multistandard outputs are pulledto logic
LO.
Table2: Data Commands
Command
Number
Function Code Programs 20 Programs D0 D1 D2 D3 D4
EOT
Program1
Program2
Program3
Program4
Program5
Program6
EOT
Program1
Program2
Program3
Program4
Program5
Program6
Program7
Program8
Program9
Program10
Program11
Program12
Program7
Program8
Program9
Program010 (decade) 10(decade)
Program13
Program14
Program15
Program16
Normalise
Volumeup
NOP
NOP
NOP
Normalise
Volumeup
Volume down
Contrastup
Contrastdown
Brightnessup
Brightness down
Saturationup
Volume down
Contrastup
Contrast down
Brightnessup
Brightness down
Saturationup
Saturation down
Memory Seq.up.
Memory Seq. down
On/standby (toggle)
Standby
Mute (toggle)
Saturation down
Memory Seq.up.
Memory Seq. down
On/standby (toggle)
Standby
Mute (toggle) TRANSMISSION (pulled up) 1 1 1 1
The above table shownthe difference betweenthe16and 20program options with respect tothe Data input commands.
Commands10,11,12&13 change function betweenthetwo options.Commands14,15&16 shouldnotbe usedinthe20 program option, they haveno function.
NOP=No operation.
M494
11/22

Partno	Mfg	Dc	Qty	Available	Descript
M494B1	SGS-THOMSON	N/a	482	avai	Single-chip voltage tuning system with 4 analog controls and uP interface