Bridgetek FT801 - Audio playback

To Next Page

To Previous Page

FT800 Series Programmer Guide

Version 2.1

Document Reference No.: BRT_000030 Clearance No.: BRT#037

Product Page

2.4 Audio playback

FT800 supports three types of audio format: 4 Bit IMA ADPCM, 8 Bit signed PCM, 8 Bit u-

Law. For IMA ADPCM format, please note the byte order: within one byte, first sample

(4 bits) shall locate from bit 0 to bit 3, while the second sample (4 bits) shall locate from

bit 4 to bit 7.

For the audio data in FT800 RAM to play, FT800 requires the start address in

REG_PLAYBACK_START to be 64 bit (8 Bytes) aligned. In addition, the length of audio

data specified by REG_PLAYBACK_LENGTH is required to be 64 bit (8 Bytes) aligned.

To learn how to play back the audio data, please check the sample code below:

wr8(REG_VOL_PB,0xFF);//configure audio playback volume

wr32(REG_PLAYBACK_START,0);//configure audio buffer starting address

wr32(REG_PLAYBACK_LENGTH,100*1024);//configure audio buffer length

wr16(REG_PLAYBACK_FREQ,44100);//configure audio sampling frequency

wr8(REG_PLAYBACK_FORMAT,ULAW_SAMPLES);//configure audio format

wr8(REG_PLAYBACK_LOOP,0);//configure once or continuous playback

wr8(REG_PLAYBACK_PLAY,1);//start the audio playback

Code snippet 5 Audio playback

AudioPlay_Status = rd8(REG_PLAYBACK_PLAY);//1-audio playback is going on,

0-audio playback has finished

Code snippet 6 Check the status of audio playback

wr32(REG_PLAYBACK_LENGTH,0);//configure the playback length to 0

wr8(REG_PLAYBACK_PLAY,1);//start audio playback

Code snippet 7 Stop the audio playback