LCD Controller

10 /24

Issue date: 13 August, 1999

Syntek Semiconductor Co., Ltd.

STK55C324

* It is not necessary to add SEI and CLI instructions in interrupt routine . If a CLI instruction is added

in the interrupt routine, then another interrupt may be inserted during current interrupt routine and may

cause stack overflow.

6.4 Sound channel operation :

6.4.1 If two sound channels are used and the SOUND1 and SOUND2 are tied together, then please follow

below instructions to make two sound channels work.

1). All channels off.

a. Set $1013 to zero.

b. Set $1008 and $1009 to zero .

2). Channel 1 output tone and channel 2 output voice or turn off .

a. Set $1013 to 0BH.

b. Set $1009 to zero to turn off or set the volume according to the voice data.

c. Set $1008 to the desired volume.

d. Set sound generator to the desired frequency.

3). Channel 2 output tone and channel 1 output voice or turn off.

a. Set $1013 to 0EH.

b. Set $1008 to zero to turn off or set the volume according to the voice data.

c. Set $1009 to the desired volume.

d. Set sound generator to the desired frequency.

4). Channel 1 output voice or turns off and channel 2 output voice or turns off.

a. Set $1013 to 0AH.

b. Set $1009 to zero to turn off or set the volume according to the voice data..

c. Set $1008 to zero to turn off or set the volume according to the voice data.

Note : If both of these two channels are off, then $1013 should be set to zero. (see item 1)

5). Two channels output tone.

a. Set $1013 to 0FH.

b. Set $1008 and $1009 to the desired volumes.

c. Set sound generators to the desired frequency.

6.4.2 If only one channel is used or two channels are used but they are not tied together, then follow below

instructions.

1). Channel off.

a. Set SOUND output to CMOS output (bit 1 or bit 3 of $1013 to zero).

b. Set volume to zero ($1008 or $1009).

2). Channel output tone.

a. Set SOUND output to DAC output (bit 1 or bit 3 of $1013 to one).

b. Set sound generator to the desired frequency.

c. Set the channel volume ($1008 or $1009).

d. Enable sound generator (bit 0 or bit 2 of $1013 to one).

3). Channel output voice.

a. Set SOUND output to DAC output (bit 1 or bit 3 of $1013 to one).

b. Disable sound generator (bit 0 or bit 2 of $1013 to zero).