SPC08A

6.9. Speech and Melody

Since SPC08A provides 6.5K ROM (0.5K for Sunplus test program)

only, it is a suitable IC for simple speech and melody synthesis.

For speech synthesis, SPC08A 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.

6.10. Power Saving Mode

The SPC08A provides a power saving mode (Standby mode) for

those applications that require very low stand-by current.

To

enter standby mode, the Wake-Up Register should be enabled

and then stop the CPU clock by writing the STOP CLOCK

Register. The CPU will then go to the stand-by mode. In such a

mode, RAM and I/Os will remain in their previous states until being

awakened. Port IOD5 - 0 are the wake-up sources in SPC08A.

After SPC08A is awakened, the internal CPU will go to the RESET

State (Tw ≧ 65536 x T1) and then continue processing the

program. Wakeup Reset will not affect the contents of RAM and

I/Os (FIG.1).

T1

Tw

CPU

CLK

Sleep

Wake-up

Reset

FIG. 1

T1 = 1 / (Fcpu), Tw ≧ 65536 x T1

© Sunplus Technology Co., Ltd.

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SEP. 19, 2001

Version: 1.7