p igmon / Mbed 2 deprecated i2s_test_sample

Part of MicroGen4 Music Synthesizer Program. (But not test it yet.) I2S ,DMA ,Stereo ,16Bit Dac(PCM1781) See detail: http://www.geocities.jp/micro_diys/index2

Dependencies:   mbed

Now added generate Saw Wave to DAC function in generate(); You will hear Stereo saw wave sound now. /media/uploads/p_igmon/i2s_sample_test_audacity.png

more info: http://www.geocities.jp/micro_diys/i2s_test_sample/i2s_test_sample.html

Synthesizer.cpp@0:dc88722ab141, 2014-07-03 (annotated)

Committer:
p_igmon
Date:
Thu Jul 03 11:59:07 2014 +0000
Revision:
0:dc88722ab141
Child:
1:48f506a7b488
Part of MicroGen4 Music Syntesizer program.

; I2S DMA Stereo DAC (PCM1781)

; http://www.geocities.jp/micro_diys/index2

Who changed what in which revision?

UserRevisionLine numberNew contents of line
p_igmon 0:dc88722ab141 1 /*
p_igmon 0:dc88722ab141 2 COPYRIGHT(c) 2014 p.igmon
p_igmon 0:dc88722ab141 3 */
p_igmon 0:dc88722ab141 4
p_igmon 0:dc88722ab141 5 #include "synthesizer.h"
p_igmon 0:dc88722ab141 6
p_igmon 0:dc88722ab141 7 /* DMA WAVE BUFFER */
p_igmon 0:dc88722ab141 8 extern S16 DMA_Buffer[];
p_igmon 0:dc88722ab141 9 extern __IO BUFFER_StateTypeDef BufferOffset;
p_igmon 0:dc88722ab141 10
p_igmon 0:dc88722ab141 11 void wave_generate(void){
p_igmon 0:dc88722ab141 12 U16 count;
p_igmon 0:dc88722ab141 13 S16 rch,lch;// 16bit stereo
p_igmon 0:dc88722ab141 14 volatile S16 *ptr0;
p_igmon 0:dc88722ab141 15
p_igmon 0:dc88722ab141 16 if (BufferOffset == DMA_FullComplete){
p_igmon 0:dc88722ab141 17 ptr0 = (S16 *)&DMA_Buffer[DMA_BUFFERSIZE>>1];// From Half
p_igmon 0:dc88722ab141 18 }else{
p_igmon 0:dc88722ab141 19 ptr0 = (S16 *)&DMA_Buffer[0];// From Top
p_igmon 0:dc88722ab141 20 }
p_igmon 0:dc88722ab141 21 BufferOffset = DMA_Idle;
p_igmon 0:dc88722ab141 22
p_igmon 0:dc88722ab141 23 count = DMA_BUFFERSIZE/4;
p_igmon 0:dc88722ab141 24 while(count-- > 0){
p_igmon 0:dc88722ab141 25
p_igmon 0:dc88722ab141 26 /* generate wave here */
p_igmon 0:dc88722ab141 27 // lch = .....
p_igmon 0:dc88722ab141 28 // rch = .....
p_igmon 0:dc88722ab141 29 *ptr0++ = lch;
p_igmon 0:dc88722ab141 30 *ptr0++ = rch;
p_igmon 0:dc88722ab141 31 }
p_igmon 0:dc88722ab141 32 }