SAA3004T データシートの表示（PDF） - Philips Electronics

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SAA3004T

Remote control transmitter

Philips Electronics 

Philips Semiconductors

Remote control transmitter

Product specification

SAA3004

be hard-wired for sub-system address 2 by connecting DRV1N to ADRM. If now DRV3N is added to ADRM by a key or

a switch, the transmitted sub-system address changes to 4.

A change of the sub-system address will not start a transmission.

Remote control signal output (REMO)

The REMO signal output stage is a push-pull type. In the HIGH state a bipolar emitter−follower allows a high output

current. The timing of the data output format is listed in Tables 1 and 2.

The information is defined by the distance tb between the leading edges of the flashed pulses or the first edge of the

modulated pulses (see Fig.3).

The format of the output data is given in Figs 2 and 3. In the flashed transmission mode the data word starts with two

toggle bits T1 and T0, followed by three bits for defining the sub-system address S2, S1 and S0, and six bits F, E, D, C,

B and A, which are defined by the selected key.

In the modulated transmission mode the first toggle bit T1 is replaced by a constant reference time bit (REF). This can

be used as a reference time for the decoding sequence.

The toggle bits function as an indication for the decoder that the next instruction has to be considered as a new

command.

The codes for the sub−system address and the selected key are given in Tables 3 and 4.

Oscillator input/output (OSCI and OSCO)

The external components must be connected to these pins when using an oscillator with a ceramic resonator.

The oscillator frequency may vary between 400 kHz and 500 kHz as defined by the resonator.

FUNCTIONAL DESCRIPTION

Keyboard operation

In the stand-by mode all drivers (DRV0N to DRV6N) are on. Whenever a key is pressed, one or more of the sense inputs

(SENnN) are tied to ground. This will start the power-up sequence. First the oscillator is activated and after the debounce

time tDB (see Fig.4) the output drivers (DRV0N to DRV6N) become active successively.

Within the first scan cycle the transmission mode, the applied sub-system address and the selected command code are

sensed and loaded into an internal data latch. In contradiction to the command code the sub-system address is sensed

only within the first scan cycle. If the applied sub-system address is changed while the command key is pressed, the

transmitted sub-system address is not altered.

In a multiple key-stroke sequence (see Fig.5) the command code is always altered in accordance with the sensed key.

Multiple key-stroke protection

The keyboard is protected against multiple key-strokes. If more than one key is pressed at the same time, the circuit will

not generate a new output at REMO (see Fig.5). In case of a multiple key-stroke the scan repetition rate is increased to

detect the release of a key as soon as possible.

There are two restrictions caused by the special structure of the keyboard matrix:

• The keys switching to ground (code numbers 7, 15, 23, 31, 39, 47, 55 and 63) and the keys connected to SEN5N and

SEN6N are not covered completely by the multiple key protection. If one sense input is switched to ground, further

keys on the same sense line are ignored.

• SEN5N and SEN6N are not protected against multiple key-stroke on the same driver line, because this condition has

been used for the definition of additional codes (code numbers 56 to 63).

August 1982

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