SGS Thomson Microelectronics M3004LAB1 Datasheet

FLASHEDOR MODULATED TRANSMISSION

7 SUB-SYSTEMADDRESSES

UP TO 64 COMMANDS PER SUB-SYSTEM ADDRESS

HIGH-CURRENT REMOTE OUTPUT AT

=6V(–IOH= 80mA)

LOW NUMBER OF ADDITIONAL COMPONENTS

KEY RELEASE DETECTION BY TOGGLE BITS

VERYLOWSTAND-BYCURRENT (< 2µA)

OPERATIONAL CURRENT < 1mA AT 6V SUPPLY

SUPPLYVOLTAGE RANGE 2 TO6.5V

CERAMIC RESONATOR CONTROLLED FREQUENCY(typ. 450kHz)

M3004LAB1

M3004LD

REMOTECONTROLTRANSMITTER

DIP20

(Plastic Package)

ORDER CODE : M3004LAB1

DESCRIPTION

The M3004LAB1/M3004LDtransmitter IC are designed for infrared remote control systems. It has a total of 448 commandswhich are divided into 7 sub-systemgroups with 64 commands each. The sub-systemcodemay be selectedby a press button, a slider switch or hardwired.

The M3004LAB1/M3004LD generate the pattern for driving the output stage. These patterns are pulse distance coded. The pulses are infrared flashes or modulated. The transmission mode is defined in conjunction with the sub-system address. Modulated pulses allow receivers with narrow-band preamplifiers for improved noise rejection to be used. Flashed pulses require a wide-bandpreamplifierwithin the receiver.

(Plastic Package)

ORDER CODE : M3004LD

PIN CONNECTIONS

1 2 3 4 5 6 7 8 9 10

REMO SEN6N SEN5N SEN4N SEN3N SEN2N SEN1N SEN0N

ADRM

SO20

20 19

17 16 15 14

12 11

DRV 6N DRV 6N DRV 6N DRV 6N

DRV 6N DRV 6N

DRV 6N OSC OUT OSC IN

3004L-01.EPS

June 1992

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M3004LAB1 - M3004LD

BLOCK DIAGRAM

S E

N P

U T

DRVOUTPUTS

0N 1N 3N 4N 5N 6N2N

KEYBOARD

ADRM

OSCILLATOR

OSCI OSCO

SCAN

PULSE

DISTANCE

MODULATOR

CONTROL

LOGIC

REMO OUTPUT

3004L-02.EPS

INPUTSANDOUTPUTS Key matrix inputs and outputs (DRV0N to

DRV6Nand SEN0N to SEN6N) Thetransmitterkeyboardis arrangedas ascanned matrix.The matrix consists of 7 driveroutputs and 7 sense inputs as shown in Figure 1. The driver outputs DRV0Nto DRV6Nare opendrainN-channel tran-sistors and they are conductive in the stand-by mode. The 7 sense inputs (SEN0N to SEN6N) enable the generation of 56 command codes.With 2externaldiodesall64commandsare addressable. The sense inputs have P-channel pull-uptransistors so that they are HIGH until they are pulled LOW by connectingthem to an output viaa keydepressiontoinitiatea codetransmission.

ADDRESS MODEINPUT (ADRM) The sub-system address and the transmission

mode are defined by connecting the ADRM input to one or more driveroutputs (DRV0Nto DRV6N) of the key matrix. If more than one driver is connected to ADRM, they must be decoupled by diodes. This allows the definition of seven sub-systemaddressesasshownintable3.If driver DRV6N is connected to ADRM, the data output

format of REMO is modulated or if not connected, flashed.

The ADRM input has switched pull-up and pulldown loads. In the stand-by mode only the pulldown device is active. Whether ADRM is open (sub-system address 0, flashed mode) or connected to the driver outputs,this input is LOW and will not cause unwanted dissipation. When the transmitterbecomesactive by pressing a key, the pull-down device is switched off and the pull-up device is switched on, so that the applied driver signalsaresensedfor thedecodingof the sub-system addressand the mode of transmission.

The arrangement of the sub-systemaddress coding is such that only the driver DRVnM with the highest number (n) defines the sub-system address,e.g. if driversDRV2N and DRV4Nare connected to ADRM, only DRV4N will define the sub-system address. This option can be used in systems requiring more than one sub-system address. The transmitter may be hard-wired for subsystemaddress2by connectingDRV1Nto ADRM. If now DRV3N is added to ADRM by a key or a switch, t h e tran smitte d sub-system a d dress changesto 4. Achangeof the sub-systemaddress will not starta transmission.

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REMOTECONTROLSIGNAL OUTPUT (REMO)

The REMO signaloutput stage is a push-pulltype. In the HIGHstate, a bipolaremitter-followerallows a highoutput current.Thetimingofthedataoutput formatis listedin tables1 and2.The informationis defined by the distance t

between the leading

edgesof the flashedpulsesor the first edgeof the modulatedpulses (see Figure3). Theformatof the output data is given in Figures 2 and 3. The data wordstarts withtwotoggle bitsT1 andT0,followed by three bits for defining the sub-system address S2,S1andS0,andsixbitsF,E,D,C,BandAwhich are defined by the selected key.

Inthemodulatedtransmissionmodethe firsttoggle bit is replaced by a constant reference time bit (REF).Thiscanbe usedasareferencetimefor the decodingsequence. The toggle bits function is an indicationfor the decoder that the next instruction has to be considered as a new command. The codesfor thesub-systemaddress andtheselected key are given in tables3 and 4.

The REMO output is protectedagainst ”Lock-up”, i.e.thelengthof anoutputpulseislimitedto<1ms, even if the oscillatorstops during an outputpulse. This avoids the rapid discharge of the battery that would otherwise be caused by the continuousactivationof the LED.

OSCILLATORINPUT / OUTPUT

(OSCIand OSCO) The external components must be connected to

these pins when usingan oscillatorwith a ceramic resonator. The oscillator frequency may vary between350kHzand600kHzasdefinedbythe resonator.

FUNCTIONAL DESCRIPTION Keyboardoperation

In the stand-by mode all drivers (DRV0N to DRV6N)areon (lowimpedancetoV

). Whenever

a key is pressed, one or more of the sense inputs (SENnN) are tied to ground. This will start the power-upsequence. Firsttheoscillatorisactivated and afterthe debouncetime t

(see Figure 4) the

output drivers (DRV0N to DRV6N) become active successively.

Within the first scan cycle the transmissionmode, the applied sub-system address and the selected

command code are sensed and loaded into an internal data latch.

In contrast to the commandcode, the sub-system is sensed only within the first scan cycle. If the applied sub-system address is changed while the commandkey is pressed,the transmittedsub-system addressis not altered.

In a multiple key stroke sequence (see Figure 5) the commandcodeisalways alteredinaccordance with the sensed key.

MULTIPLEKEY-STROKEPROTECTION

The keyboard is protected against multiple keystrokes. If more than one key is pressed at the sametime,thecircuitwillnotgenerateanewoutput at REMO (see Figure 5). In case of a multiple key-stroke,the scan repetition rate is increasedto detect the release of a key as soon as possible.

There are two restrictions caused by the special structureof the keyboard matrix :

- The keys switching to ground(code numbers 7, 15, 23, 31, 39, 47, 55 and 63) and the keys connectedtoSEN5NandSEN6Narenotcovered completelyby the multiple key protection. If one sense inputisswitchedto ground,further keyson the same sense line are ignored, i.e. the command code corresponding to ”key to ground” is transmitted.

- SEN5N and SEN6N are not protected against multiple keystroke on the same driver line, because this condition has been used for the definition ofadditionalcodes(codenumber56to 63).

OUTPUTSEQUENCE(data format) The output operation will start when the selected

code is found. A burst of pulses, including the latchedaddressandcommandcodes,is generated at the output REMO as long as a key is pressed. The format of the output pulse train is given in Figures 2 and 3. The operation is terminated by releasingthe keyorifmorethanonekeyispressed at the same time. Once a sequenceis started, the transmitted data words will always be completed after the key is released.

The toggle bits T0 and T1 are incremented if the key is released for a minimum time t

REL

(see Figure 4). The toggle bits remain unchanged within a multiplekey-stroke sequence.

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