Sunplus Technology Co., Ltd.

Rev.: 1.0

1999.11.04

SPC500A1

6

TIMER/COUNTER

The SPC500A1 contains two 12-bit timer/counters, TMA and TMB respectively.

TMA can be specified as a

timer or a counter, but TMB can only be used as a timer.

In the timer mode, TMA and TMB are re-loaded up-

counters.

When timer overflows from $0FFF to $0000, the carry signal will make the timer automatically reload

to the user’s pre-set value and be up-counted again. At the same time, the carry signal will generate the INT

signal if the corresponding bit is enabled in the INT ENABLE Register.

If TMA is specified as a counter, users

can reset by loading #0 into the counter. After the counter has been activated, the value of the counter can also

be read from the counters at the same time.

Clock source of Timer/Counter can be selected as follows:

Timer/Counter

Clock Source

12-BIT TIMER

CPU CLOCK (T) or T/4

TMA

12-BIT COUNTER

T/64, T/8192, T/65536 or EXT CLK

TMB

12-BIT TIMER

T or T/4

MODE SELECT REGISTER

TMA only, select timer or counter

TIMER CLOCK SELECTOR

Select T or T/4

SPEECH AND MELODY

Since the SPC500A1 provides a large ROM and wide range of CPU operation speeds, it is most suitable for

speech and melody synthesis.

For speech synthesis, the SPC500A1 can provide NMI for accurate sampling

frequency.

Users can record or synthesize the sound and digitize it into the ROM.

The sound data can be

played back in the sequence of the control functions as designed by the user's program.

Several algorithms

are recommended for high fidelity and compression of sound including PCM, LOG PCM, and ADPCM.

For

melody synthesis, the SPC500A1 provides the dual tone mode.

After selecting the dual tone mode, users only

need to fill either TMA or TMB, or both TMA and TMB to generate expected frequency for each channel.

The

hardware will toggle the tone wave automatically without entering into an interrupt service routine.

Users are

able to simulate musical instruments or sound effects by simply controlling the envelope of tone output.

SERIAL INTERFACE I/O

The SPC500A1 provides serial interface I/O mode for those applications requiring large ROM/RAM.

Serial

Interface I/O Port can be used to read/write data from/to extra memory.

The interface I/O Register is the

control register for programming interface I/O.

MULTI-DUTY CYCLE MODE

The SPC500A1 provides three output waveforms, 1/2, 1/3, and 1/4 duty cycles.

The Control Register should

be used to select 1/2, 1/3 or 1/4 duty cycle and the IOA2 should be programmed as the multi-duty cycle output

port.

Users can use the combinations of these duty cycles for remote-control purposes.