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dpgeorgedpgeorge
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stm: Add DMA support to Audio object.
1 parent 2da9830 commit 5322ec0

1 file changed

Lines changed: 161 additions & 53 deletions

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‎stm/audio.c‎

Lines changed: 161 additions & 53 deletions
Original file line numberDiff line numberDiff line change
@@ -1,8 +1,6 @@
11
#include <stdint.h>
22
#include <string.h>
33

4-
#include "stm32f4xx_rcc.h"
5-
#include "stm32f4xx_gpio.h"
64
#include "stm32f4xx_dac.h"
75

86
#include "nlr.h"
@@ -11,80 +9,195 @@
119
#include "qstr.h"
1210
#include "parse.h"
1311
#include "obj.h"
12+
#include "map.h"
1413
#include "runtime.h"
1514

1615
#include "audio.h"
1716

18-
#define SAMPLE_BUF_SIZE (32)
17+
STATIC void TIM7_Config(uint freq) {
18+
// TIM7 clock enable
19+
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM7, ENABLE);
1920

20-
// sample_buf_in is always the same or ahead of sample_buf_out
21-
// when they are the same, there are no more samples left to process
22-
// in this scheme, there is always 1 unusable byte in the buffer, just before sample_buf_out
23-
int sample_buf_in;
24-
int sample_buf_out;
25-
byte sample_buf[SAMPLE_BUF_SIZE];
21+
// reset TIM7
22+
TIM_DeInit(TIM7);
2623

27-
bool audio_is_full(void) {
28-
return ((sample_buf_in + 1) % SAMPLE_BUF_SIZE) == sample_buf_out;
29-
}
24+
// Compute the prescaler value so TIM7 triggers at freq-Hz
25+
uint16_t period = (uint16_t) ((SystemCoreClock / 2) / freq) - 1;
3026

31-
void audio_fill(byte sample) {
32-
sample_buf[sample_buf_in] = sample;
33-
sample_buf_in = (sample_buf_in + 1) % SAMPLE_BUF_SIZE;
34-
// enable interrupt
35-
}
27+
// Time base configuration
28+
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
29+
TIM_TimeBaseStructure.TIM_Period = period; // timer triggers with this period
30+
TIM_TimeBaseStructure.TIM_Prescaler = 0; // timer runs at SystemCoreClock / 2
31+
TIM_TimeBaseStructure.TIM_ClockDivision = 0; // unused for TIM7
32+
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; // unused for TIM7
33+
TIM_TimeBaseInit(TIM7, &TIM_TimeBaseStructure);
3634

37-
void audio_drain(void) {
38-
if (sample_buf_in == sample_buf_out) {
39-
// buffer is empty; disable interrupt
40-
} else {
41-
// buffer has a sample; output it
42-
byte sample = sample_buf[sample_buf_out];
43-
DAC_SetChannel2Data(DAC_Align_8b_R, sample);
44-
sample_buf_out = (sample_buf_out + 1) % SAMPLE_BUF_SIZE;
45-
}
35+
// TIM7 TRGO selection
36+
TIM_SelectOutputTrigger(TIM7, TIM_TRGOSource_Update);
37+
38+
// TIM7 enable counter
39+
TIM_Cmd(TIM7, ENABLE);
4640
}
4741

4842
/******************************************************************************/
4943
// Micro Python bindings
5044

5145
typedef struct _pyb_audio_t {
5246
mp_obj_base_t base;
53-
int dac_id; // 1 or 2
47+
uint dac_channel; // DAC_Channel_1 or DAC_Channel_2
48+
DMA_Stream_TypeDef *dma_stream; // DMA1_Stream6 or DMA1_Stream7
5449
} pyb_audio_t;
5550

51+
mp_obj_t pyb_audio_noise(mp_obj_t self_in, mp_obj_t freq) {
52+
pyb_audio_t *self = self_in;
53+
54+
// set TIM7 to trigger the DAC at the given frequency
55+
TIM7_Config(mp_obj_get_int(freq));
56+
57+
DAC_Cmd(self->dac_channel, DISABLE);
58+
59+
DAC_InitTypeDef DAC_InitStructure;
60+
DAC_InitStructure.DAC_Trigger = DAC_Trigger_T7_TRGO;
61+
DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_Noise;
62+
DAC_InitStructure.DAC_LFSRUnmask_TriangleAmplitude = DAC_LFSRUnmask_Bits10_0;
63+
DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Enable;
64+
DAC_Init(self->dac_channel, &DAC_InitStructure);
65+
66+
DAC_Cmd(self->dac_channel, ENABLE);
67+
68+
if (self->dac_channel == DAC_Channel_1) {
69+
DAC_SetChannel1Data(DAC_Align_12b_L, 0x7ff0);
70+
} else {
71+
DAC_SetChannel2Data(DAC_Align_12b_L, 0x7ff0);
72+
}
73+
74+
return mp_const_none;
75+
}
76+
77+
mp_obj_t pyb_audio_triangle(mp_obj_t self_in, mp_obj_t freq) {
78+
pyb_audio_t *self = self_in;
79+
80+
// set TIM7 to trigger the DAC at the given frequency
81+
TIM7_Config(mp_obj_get_int(freq));
82+
83+
DAC_Cmd(self->dac_channel, DISABLE);
84+
85+
DAC_InitTypeDef DAC_InitStructure;
86+
DAC_InitStructure.DAC_Trigger = DAC_Trigger_T7_TRGO;
87+
DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_Triangle;
88+
DAC_InitStructure.DAC_LFSRUnmask_TriangleAmplitude = DAC_TriangleAmplitude_1023;
89+
DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Enable;
90+
DAC_Init(self->dac_channel, &DAC_InitStructure);
91+
92+
DAC_Cmd(self->dac_channel, ENABLE);
93+
94+
// set base value of triangle wave
95+
if (self->dac_channel == DAC_Channel_1) {
96+
DAC_SetChannel1Data(DAC_Align_12b_R, 0x100);
97+
} else {
98+
DAC_SetChannel2Data(DAC_Align_12b_R, 0x100);
99+
}
100+
101+
return mp_const_none;
102+
}
103+
56104
// direct access to DAC
57105
mp_obj_t pyb_audio_dac(mp_obj_t self_in, mp_obj_t val) {
58106
pyb_audio_t *self = self_in;
59-
if (self->dac_id == 1) {
107+
if (self->dac_channel == DAC_Channel_1) {
60108
DAC_SetChannel1Data(DAC_Align_8b_R, mp_obj_get_int(val));
61109
} else {
62110
DAC_SetChannel2Data(DAC_Align_8b_R, mp_obj_get_int(val));
63111
}
64112
return mp_const_none;
65113
}
66114

67-
mp_obj_t pyb_audio_is_full(mp_obj_t self_in) {
68-
if (audio_is_full()) {
69-
return mp_const_true;
115+
#define DAC_DHR8R1_ADDRESS (DAC_BASE + 0x10)
116+
#define DAC_DHR8R2_ADDRESS (DAC_BASE + 0x1c)
117+
118+
// initiates a burst of RAM->DAC using DMA
119+
// input data is treated as an array of bytes (8 bit data)
120+
// TIM7 is used to set the frequency of the transfer
121+
mp_obj_t pyb_audio_dma(uint n_args, const mp_obj_t *args, mp_map_t *kw_args) {
122+
pyb_audio_t *self = args[0];
123+
124+
// set TIM7 to trigger the DAC at the given frequency
125+
TIM7_Config(mp_obj_get_int(args[2]));
126+
127+
mp_obj_type_t *type = mp_obj_get_type(args[1]);
128+
if (type->buffer_p.get_buffer == NULL) {
129+
nlr_jump(mp_obj_new_exception_msg(&mp_type_TypeError, "buffer argument must support buffer protocol"));
130+
}
131+
buffer_info_t bufinfo;
132+
type->buffer_p.get_buffer(args[1], &bufinfo, BUFFER_READ);
133+
134+
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA1, ENABLE);
135+
136+
DMA_Cmd(self->dma_stream, DISABLE);
137+
while (DMA_GetCmdStatus(self->dma_stream) != DISABLE) {
138+
}
139+
140+
DAC_Cmd(self->dac_channel, DISABLE);
141+
142+
// DAC channel configuration
143+
DAC_InitTypeDef DAC_InitStructure;
144+
DAC_InitStructure.DAC_Trigger = DAC_Trigger_T7_TRGO;
145+
DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_None;
146+
DAC_InitStructure.DAC_LFSRUnmask_TriangleAmplitude = DAC_TriangleAmplitude_1; // unused, but need to set it to a valid value
147+
DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Enable;
148+
DAC_Init(self->dac_channel, &DAC_InitStructure);
149+
150+
// DMA1_Stream[67] channel7 configuration
151+
DMA_DeInit(self->dma_stream);
152+
DMA_InitTypeDef DMA_InitStructure;
153+
DMA_InitStructure.DMA_Channel = DMA_Channel_7;
154+
if (self->dac_channel == DAC_Channel_1) {
155+
DMA_InitStructure.DMA_PeripheralBaseAddr = DAC_DHR8R1_ADDRESS;
70156
} else {
71-
return mp_const_false;
157+
DMA_InitStructure.DMA_PeripheralBaseAddr = DAC_DHR8R2_ADDRESS;
72158
}
73-
}
159+
DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)bufinfo.buf;
160+
DMA_InitStructure.DMA_DIR = DMA_DIR_MemoryToPeripheral;
161+
DMA_InitStructure.DMA_BufferSize = bufinfo.len;
162+
DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
163+
DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
164+
DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
165+
DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
166+
mp_map_elem_t *kw_mode = mp_map_lookup(kw_args, MP_OBJ_NEW_QSTR(qstr_from_str("mode")), MP_MAP_LOOKUP);
167+
DMA_InitStructure.DMA_Mode = kw_mode == NULL ? DMA_Mode_Normal : mp_obj_get_int(kw_mode->value); // normal = 0, circular = 0x100
168+
DMA_InitStructure.DMA_Priority = DMA_Priority_High;
169+
DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;
170+
DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull;
171+
DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;
172+
DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
173+
DMA_Init(self->dma_stream, &DMA_InitStructure);
174+
175+
// enable DMA stream
176+
DMA_Cmd(self->dma_stream, ENABLE);
177+
while (DMA_GetCmdStatus(self->dma_stream) == DISABLE) {
178+
}
179+
180+
// enable DAC channel
181+
DAC_Cmd(self->dac_channel, ENABLE);
182+
183+
// enable DMA for DAC channel
184+
DAC_DMACmd(self->dac_channel, ENABLE);
185+
186+
//printf("DMA: %p %lu\n", bufinfo.buf, bufinfo.len);
74187

75-
mp_obj_t pyb_audio_fill(mp_obj_t self_in, mp_obj_t val) {
76-
audio_fill(mp_obj_get_int(val));
77188
return mp_const_none;
78189
}
79190

191+
STATIC MP_DEFINE_CONST_FUN_OBJ_2(pyb_audio_noise_obj, pyb_audio_noise);
192+
STATIC MP_DEFINE_CONST_FUN_OBJ_2(pyb_audio_triangle_obj, pyb_audio_triangle);
80193
STATIC MP_DEFINE_CONST_FUN_OBJ_2(pyb_audio_dac_obj, pyb_audio_dac);
81-
STATIC MP_DEFINE_CONST_FUN_OBJ_1(pyb_audio_is_full_obj, pyb_audio_is_full);
82-
STATIC MP_DEFINE_CONST_FUN_OBJ_2(pyb_audio_fill_obj, pyb_audio_fill);
194+
STATIC MP_DEFINE_CONST_FUN_OBJ_KW(pyb_audio_dma_obj, 3, pyb_audio_dma);
83195

84196
STATIC const mp_method_t pyb_audio_methods[] = {
197+
{ "noise", &pyb_audio_noise_obj },
198+
{ "triangle", &pyb_audio_triangle_obj },
85199
{ "dac", &pyb_audio_dac_obj },
86-
{ "is_full", &pyb_audio_is_full_obj },
87-
{ "fill", &pyb_audio_fill_obj },
200+
{ "dma", &pyb_audio_dma_obj },
88201
{ NULL, NULL },
89202
};
90203

@@ -94,8 +207,8 @@ STATIC const mp_obj_type_t pyb_audio_type = {
94207
.methods = pyb_audio_methods,
95208
};
96209

97-
STATIC const pyb_audio_t pyb_audio_channel_1 = {{&pyb_audio_type}, 1};
98-
STATIC const pyb_audio_t pyb_audio_channel_2 = {{&pyb_audio_type}, 2};
210+
STATIC const pyb_audio_t pyb_audio_channel_1 = {{&pyb_audio_type}, DAC_Channel_1, DMA1_Stream5};
211+
STATIC const pyb_audio_t pyb_audio_channel_2 = {{&pyb_audio_type}, DAC_Channel_2, DMA1_Stream6};
99212

100213
// create the audio object
101214
// currently support either DAC1 on X5 (id = 1) or DAC2 on X6 (id = 2)
@@ -106,17 +219,14 @@ STATIC mp_obj_t pyb_Audio(mp_obj_t id) {
106219

107220
int dac_id = mp_obj_get_int(id);
108221
uint pin;
109-
uint channel;
110-
mp_obj_t dac_obj;
222+
const pyb_audio_t *dac_obj;
111223

112224
if (dac_id == 1) {
113225
pin = GPIO_Pin_4;
114-
channel = DAC_Channel_1;
115-
dac_obj = (mp_obj_t)&pyb_audio_channel_1;
226+
dac_obj = &pyb_audio_channel_1;
116227
} else {
117228
pin = GPIO_Pin_5;
118-
channel = DAC_Channel_2;
119-
dac_obj = (mp_obj_t)&pyb_audio_channel_2;
229+
dac_obj = &pyb_audio_channel_2;
120230
}
121231

122232
// DAC channel configuration
@@ -130,19 +240,17 @@ STATIC mp_obj_t pyb_Audio(mp_obj_t id) {
130240
DAC_InitTypeDef DAC_InitStructure;
131241
DAC_InitStructure.DAC_Trigger = DAC_Trigger_None;
132242
DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_None;
243+
DAC_InitStructure.DAC_LFSRUnmask_TriangleAmplitude = DAC_TriangleAmplitude_1023;
133244
DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Enable;
134-
DAC_Init(channel, &DAC_InitStructure);
245+
DAC_Init(dac_obj->dac_channel, &DAC_InitStructure);
135246

136247
// Enable DAC Channel
137-
DAC_Cmd(channel, ENABLE);
248+
DAC_Cmd(dac_obj->dac_channel, ENABLE);
138249

139250
// from now on use DAC_SetChannel[12]Data to trigger a conversion
140251

141-
sample_buf_in = 0;
142-
sample_buf_out = 0;
143-
144252
// return static object
145-
return dac_obj;
253+
return (mp_obj_t)dac_obj;
146254
}
147255

148256
MP_DEFINE_CONST_FUN_OBJ_1(pyb_Audio_obj, pyb_Audio);

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