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ABOV Semiconductor Co., Ltd.
11.15.4 Automatically D/AC Data Increment/Decrement
The “automatically D/AC data increment/decrement” function is important to remove a pop noise when voice prompt
play. If this function is not embedded, a programmer have to code to reduce a pop noise on speaker. The
DACDR[15:4] value increases a curret D/AC data value to 800H with “automatically D/AC data increment” when the
ADATID bit is set to “1b” and the DACEN bit is changed to “1b” from “0b”. The DACDR[15:4] value decreases a curret
D/AC data value to 000H with “automatically D/AC data decrement” when the ADATID bit is set to “1b” and the
DACEN bit is changed to “0b” from “1b”.
How to remove a pop noise when a speaker is turn on:
− Write “05H” for 0dB to PGSR register
− Write “0000H” to D/A converter data register
− Clear D/A converter buffer register by DACBC bit set to “1b”
− Select one of the “FADPCM decoder match signal”, “Timer 0 match signal” and “Timer 1 match signal” for
D/A converter reload signal with DACRLDS[1:0] bits
− Start D/AC operation by DACEN bit set to “1b”
How to remove a pop noise when a speaker is turn off:
− Write “05H” for 0dB to PGSR register
− Keep the value of DACRLDS[1:0] bits set when speaker is turn on
− Stop D/AC operation by DACEN bit set to “0b”
DACDR[15:4] = FFFH
DACDR[15:4] = 800H
DACDR[15:4] = 000H
Auto-Increment Auto-DecrementVoice Prompt Play
- PGSR = 05H
- DACDR = 0000H
- DACCR = xx11x010b
- DACCR.DACEN = 1b
- PGSR = 0xH
- DACCR = xx00x011b
- PGSR = 05H
- DACCR = xx10x010b
Figure 11.84 A pop noise removement when a reload signal is “FADPCM decoder match signal”
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