August 1982

3

Philips Semiconductors

Product specification

Remote control transmitter

SAA3004

INPUTS AND OUTPUTS

Key matrix inputs and outputs (DRV0N to DRV6N and SEN0N to SEN6N)

The transmitter keyboard is arranged as a scanned matrix. The matrix consists of 7 driver outputs and 7 sense inputs as

shown in Fig.1. The driver outputs DRV0N to DRV6N are open drain N-channel transistors and they are conductive in

the stand-by mode. The 7 sense inputs (SEN0N to SEN6N) enable the generation of 56 command codes.

With 2 external diodes all 64 commands are addressable. The sense inputs have P-channel pull-up transistors, so that

they are HIGH until they are pulled LOW by connecting them to an output via a key depression to initiate a code

transmission.

Address mode input (ADRM)

The sub-system address and the transmission mode are defined by connecting the ADRM input to one or more driver

outputs (DRV0N to DRV6N) of the key matrix. If more than one driver is connected to ADRM, they must be decoupled

by a diode. This allows the definition of seven sub-system addresses as shown in Table 3. 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 pull-down loads. In the stand-by mode only the pull

−down 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 transmitter becomes active by pressing a key, the pull

−down device is

switched off and the pull-up device is switched on, so that the applied driver signals are sensed for the decoding of the

sub-system address and the mode of transmission.

The arrangement of the sub-system address coding is such that only the driver DRVnN with the highest number (n)

defines the sub-system address, e.g. if driver DRV2N and DRV4N are connected to ADRM, only DRV4N will define the

sub-system address. This option can be used in transmitters for more than one sub-system address. The transmitter may

Fig.1 Transmitter with SAA3004.