How to setup DAC with OpAmp for DMA
- 2 freq/tone sinewaves
- 2 freq/tone sinewaves with every halfwave changing
- 2 freq/tone sinewaves with every fullwave changing
- 2 freq/tone sinewaves with every few fullwave changing
- Dac Speed Test using sinewave
- Added DAC trigger by HRTIM external pins still troubleshooting internal trigger
use Dac3 or 4 and output to OpAmp
Trigger > Tim6 Trigger Out Event
Direction > Mem to Periph
Circular > Memory
Data width > Periph = Word (will not work if other data with or less)
Follower of DAC non-inverting output
Power Mode > High Speed
Prescaler & ARR > set accorningly, shown below is 1Mhz Trigger Event > Update event (other selection will not work)
in Main.c
/*##- Enable DAC Channel and associated DMA ##############################*/
if(HAL_OK != HAL_DAC_Start_DMA(&hdac3, DAC_CHANNEL_1,
(uint32_t*)Sine12bit, Sine12bit_SIZE, DAC_ALIGN_12B_R))
{
/* Start DMA Error */
Error_Handler();
}
/*##- Enable TIM peripheral counter ######################################*/
if(HAL_OK != HAL_TIM_Base_Start(&htim6))
{
Error_Handler();
}
/*##- Start OPAMP #####################################################*/
/* Enable OPAMP */
if(HAL_OK != HAL_OPAMP_Start(&hopamp6))
{
Error_Handler();
}
void LL_Activate_DAC3(void)
{
__IO uint32_t wait_loop_index = 0;
/* Enable DAC channel */
LL_DAC_Enable(DAC3, LL_DAC_CHANNEL_1);
/* Delay for DAC channel voltage settling time from DAC channel startup. */
/* Compute number of CPU cycles to wait for, from delay in us. */
/* Note: Variable divided by 2 to compensate partially */
/* CPU processing cycles (depends on compilation optimization). */
/* Note: If system core clock frequency is below 200kHz, wait time */
/* is only a few CPU processing cycles. */
wait_loop_index = ((LL_DAC_DELAY_STARTUP_VOLTAGE_SETTLING_US * (SystemCoreClock / (100000 * 2))) / 10);
while(wait_loop_index != 0)
{
wait_loop_index--;
}
/* Enable DAC channel trigger */
/* Note: DAC channel conversion can start from trigger enable: */
/* - if DAC channel trigger source is set to SW: */
/* DAC channel conversion will start after trig order */
/* using function "LL_DAC_TrigSWConversion()". */
/* - if DAC channel trigger source is set to external trigger */
/* (timer, ...): */
/* DAC channel conversion can start immediately */
/* (after next trig order from external trigger) */
LL_DAC_EnableTrigger(DAC3, LL_DAC_CHANNEL_1);
}
void LL_EnableDMA_DAC3(void)
{
/* Set DMA transfer addresses of source and destination */
LL_DMA_ConfigAddresses(DMA1,
LL_DMA_CHANNEL_1,
(uint32_t)&Sine12bit,
LL_DAC_DMA_GetRegAddr(DAC3, LL_DAC_CHANNEL_1, LL_DAC_DMA_REG_DATA_12BITS_RIGHT_ALIGNED),
LL_DMA_DIRECTION_MEMORY_TO_PERIPH);
/* Set DMA transfer size */
LL_DMA_SetDataLength(DMA1,
LL_DMA_CHANNEL_1,
Sine12bit_SIZE);
/* Enable DMA transfer interruption: transfer error */
// LL_DMA_EnableIT_TE(DMA1,
// LL_DMA_CHANNEL_1);
/* Note: In this example, the only DMA interruption activated is */
/* transfer error. */
/* If needed, DMA interruptions of half of transfer */
/* and transfer complete can be activated. */
/* Refer to DMA examples. */
/* Activation of DMA */
/* Enable the DMA transfer */
LL_DMA_EnableChannel(DMA1,
LL_DMA_CHANNEL_1);
/* Set DAC mode sample-and-hold timings */
// LL_DAC_SetSampleAndHoldSampleTime (DAC1, LL_DAC_CHANNEL_1, 0x3FF);
// LL_DAC_SetSampleAndHoldHoldTime (DAC1, LL_DAC_CHANNEL_1, 0x3FF);
// LL_DAC_SetSampleAndHoldRefreshTime(DAC1, LL_DAC_CHANNEL_1, 0xFF);
/* Set the mode for the selected DAC channel */
// LL_DAC_SetMode(DAC1, LL_DAC_CHANNEL_1, LL_DAC_MODE_NORMAL_OPERATION);
/* Enable DAC channel DMA request */
LL_DAC_EnableDMAReq(DAC3, LL_DAC_CHANNEL_1);
/* Enable interruption DAC channel1 under-run */
// LL_DAC_EnableIT_DMAUDR1(DAC1);
}
void LL_Activate_OPAMP6(void)
{
__IO uint32_t wait_loop_index = 0;
/* Enable OPAMP */
LL_OPAMP_Enable(OPAMP6);
/* Delay for OPAMP startup time. */
/* Compute number of CPU cycles to wait for, from delay in us. */
/* Note: Variable divided by 2 to compensate partially */
/* CPU processing cycles (depends on compilation optimization). */
/* Note: If system core clock frequency is below 200kHz, wait time */
/* is only a few CPU processing cycles. */
wait_loop_index = ((LL_OPAMP_DELAY_STARTUP_US * (SystemCoreClock / (100000 * 2))) / 10);
while(wait_loop_index != 0)
{
wait_loop_index--;
}
}
in Main.c
LL_EnableDMA_DAC3();
LL_Activate_OPAMP6();
LL_Activate_DAC3();
LL_TIM_EnableCounter(TIM6);
const uint16_t Sine12bit[32] = { 511, 611, 707, 796, 873, 937, 984, 1013,
1023, 1013, 984, 937, 873, 796, 707, 611,
511, 412, 315, 227, 149, 86, 38, 9,
0, 9, 38, 86, 149, 227, 315, 412};
for(uint16_t cntr = 0; cntr < (Sawtooth12bit_SIZE); cntr++)
Sawtooth12bit[cntr] = cntr;
for(uint16_t cntr = 0; cntr < (Sawtooth12bit_SIZE - 4000); cntr++)
Sawtooth12bit[cntr] = cntr;
const uint16_t Sine1k_15k[] = { 1861, 2597, 1744, 2099, 3102, 2379, 2300, 3419,
2936, 2435, 3499, 3329, 2482, 3329, 3499, 2435,
2936, 3419, 2300, 2379, 3102, 2099, 1744, 2597,
1861, 1126, 1979, 1624, 620, 1343, 1423, 304,
787, 1288, 224, 394, 1241, 394, 224, 1288,
787, 304, 1423, 1343, 620, 1624, 1979, 1126};
In Excel Using Line graph
In Excel Using Bar graph
Actual DAC waveform
As can be seen, Excel waveform is better than the DAC because Excel is connecting the dots, while the DAC is holding the voltage similar to bar graph
The actual waveform of Sine1k_15k is not of very good resolution. So I generated another array using Online sine generator
Sinewave 1kHz, DMA is 2MSPS (500nS)
uint32_t MySine2000[] =
{
683,685,687,689,691,693,695,698,700,702,704,706,708,710,713,715,717,719,721,723,
725,727,730,732,734,736,738,740,742,745,747,749,751,753,755,757,760,762,764,766,
768,770,772,774,777,779,781,783,785,787,789,791,793,796,798,800,802,804,806,808,
810,812,815,817,819,821,823,825,827,829,831,833,836,838,840,842,844,846,848,850,
852,854,856,858,861,863,865,867,869,871,873,875,877,879,881,883,885,887,889,891,
893,895,897,900,902,904,906,908,910,912,914,916,918,920,922,924,926,928,930,932,
934,936,938,940,942,944,946,948,950,952,954,956,957,959,961,963,965,967,969,971,
973,975,977,979,981,983,985,987,989,990,992,994,996,998,1000,1002,1004,1006,1008,1009,
1011,1013,1015,1017,1019,1021,1023,1024,1026,1028,1030,1032,1034,1035,1037,1039,1041,1043,1045,1046,
1048,1050,1052,1054,1055,1057,1059,1061,1063,1064,1066,1068,1070,1071,1073,1075,1077,1078,1080,1082,
1084,1085,1087,1089,1091,1092,1094,1096,1097,1099,1101,1103,1104,1106,1108,1109,1111,1113,1114,1116,
1118,1119,1121,1122,1124,1126,1127,1129,1131,1132,1134,1135,1137,1139,1140,1142,1143,1145,1147,1148,
1150,1151,1153,1154,1156,1157,1159,1161,1162,1164,1165,1167,1168,1170,1171,1173,1174,1176,1177,1179,
1180,1181,1183,1184,1186,1187,1189,1190,1192,1193,1194,1196,1197,1199,1200,1201,1203,1204,1206,1207,
1208,1210,1211,1212,1214,1215,1216,1218,1219,1220,1222,1223,1224,1226,1227,1228,1230,1231,1232,1233,
1235,1236,1237,1238,1240,1241,1242,1243,1245,1246,1247,1248,1249,1251,1252,1253,1254,1255,1256,1258,
1259,1260,1261,1262,1263,1264,1266,1267,1268,1269,1270,1271,1272,1273,1274,1275,1276,1277,1279,1280,
1281,1282,1283,1284,1285,1286,1287,1288,1289,1290,1291,1292,1293,1294,1294,1295,1296,1297,1298,1299,
1300,1301,1302,1303,1304,1305,1305,1306,1307,1308,1309,1310,1311,1311,1312,1313,1314,1315,1315,1316,
1317,1318,1319,1319,1320,1321,1322,1322,1323,1324,1325,1325,1326,1327,1328,1328,1329,1330,1330,1331,
1332,1332,1333,1334,1334,1335,1335,1336,1337,1337,1338,1338,1339,1340,1340,1341,1341,1342,1342,1343,
1344,1344,1345,1345,1346,1346,1347,1347,1348,1348,1349,1349,1349,1350,1350,1351,1351,1352,1352,1353,
1353,1353,1354,1354,1354,1355,1355,1356,1356,1356,1357,1357,1357,1358,1358,1358,1358,1359,1359,1359,
1360,1360,1360,1360,1361,1361,1361,1361,1362,1362,1362,1362,1362,1363,1363,1363,1363,1363,1363,1364,
1364,1364,1364,1364,1364,1364,1364,1364,1365,1365,1365,1365,1365,1365,1365,1365,1365,1365,1365,1365,
1365,1365,1365,1365,1365,1365,1365,1365,1365,1365,1365,1365,1365,1364,1364,1364,1364,1364,1364,1364,
1364,1364,1363,1363,1363,1363,1363,1363,1362,1362,1362,1362,1362,1361,1361,1361,1361,1360,1360,1360,
1360,1359,1359,1359,1358,1358,1358,1358,1357,1357,1357,1356,1356,1356,1355,1355,1354,1354,1354,1353,
1353,1353,1352,1352,1351,1351,1350,1350,1349,1349,1349,1348,1348,1347,1347,1346,1346,1345,1345,1344,
1344,1343,1342,1342,1341,1341,1340,1340,1339,1338,1338,1337,1337,1336,1335,1335,1334,1334,1333,1332,
1332,1331,1330,1330,1329,1328,1328,1327,1326,1325,1325,1324,1323,1322,1322,1321,1320,1319,1319,1318,
1317,1316,1315,1315,1314,1313,1312,1311,1311,1310,1309,1308,1307,1306,1305,1305,1304,1303,1302,1301,
1300,1299,1298,1297,1296,1295,1294,1294,1293,1292,1291,1290,1289,1288,1287,1286,1285,1284,1283,1282,
1281,1280,1279,1277,1276,1275,1274,1273,1272,1271,1270,1269,1268,1267,1266,1264,1263,1262,1261,1260,
1259,1258,1256,1255,1254,1253,1252,1251,1249,1248,1247,1246,1245,1243,1242,1241,1240,1238,1237,1236,
1235,1233,1232,1231,1230,1228,1227,1226,1224,1223,1222,1220,1219,1218,1216,1215,1214,1212,1211,1210,
1208,1207,1206,1204,1203,1201,1200,1199,1197,1196,1194,1193,1192,1190,1189,1187,1186,1184,1183,1181,
1180,1179,1177,1176,1174,1173,1171,1170,1168,1167,1165,1164,1162,1161,1159,1157,1156,1154,1153,1151,
1150,1148,1147,1145,1143,1142,1140,1139,1137,1135,1134,1132,1131,1129,1127,1126,1124,1122,1121,1119,
1118,1116,1114,1113,1111,1109,1108,1106,1104,1103,1101,1099,1097,1096,1094,1092,1091,1089,1087,1085,
1084,1082,1080,1078,1077,1075,1073,1071,1070,1068,1066,1064,1063,1061,1059,1057,1055,1054,1052,1050,
1048,1046,1045,1043,1041,1039,1037,1035,1034,1032,1030,1028,1026,1024,1023,1021,1019,1017,1015,1013,
1011,1009,1008,1006,1004,1002,1000,998,996,994,992,990,989,987,985,983,981,979,977,975,
973,971,969,967,965,963,961,959,957,956,954,952,950,948,946,944,942,940,938,936,
934,932,930,928,926,924,922,920,918,916,914,912,910,908,906,904,902,900,897,895,
893,891,889,887,885,883,881,879,877,875,873,871,869,867,865,863,861,858,856,854,
852,850,848,846,844,842,840,838,836,833,831,829,827,825,823,821,819,817,815,812,
810,808,806,804,802,800,798,796,793,791,789,787,785,783,781,779,777,774,772,770,
768,766,764,762,760,757,755,753,751,749,747,745,742,740,738,736,734,732,730,727,
725,723,721,719,717,715,713,710,708,706,704,702,700,698,695,693,691,689,687,685,
683,680,678,676,674,672,670,667,665,663,661,659,657,655,652,650,648,646,644,642,
640,638,635,633,631,629,627,625,623,620,618,616,614,612,610,608,605,603,601,599,
597,595,593,591,588,586,584,582,580,578,576,574,572,569,567,565,563,561,559,557,
555,553,550,548,546,544,542,540,538,536,534,532,529,527,525,523,521,519,517,515,
513,511,509,507,504,502,500,498,496,494,492,490,488,486,484,482,480,478,476,474,
472,470,468,465,463,461,459,457,455,453,451,449,447,445,443,441,439,437,435,433,
431,429,427,425,423,421,419,417,415,413,411,409,408,406,404,402,400,398,396,394,
392,390,388,386,384,382,380,378,376,375,373,371,369,367,365,363,361,359,357,356,
354,352,350,348,346,344,342,341,339,337,335,333,331,330,328,326,324,322,320,319,
317,315,313,311,310,308,306,304,302,301,299,297,295,294,292,290,288,287,285,283,
281,280,278,276,274,273,271,269,268,266,264,262,261,259,257,256,254,252,251,249,
247,246,244,243,241,239,238,236,234,233,231,230,228,226,225,223,222,220,218,217,
215,214,212,211,209,208,206,204,203,201,200,198,197,195,194,192,191,189,188,186,
185,184,182,181,179,178,176,175,173,172,171,169,168,166,165,164,162,161,159,158,
157,155,154,153,151,150,149,147,146,145,143,142,141,139,138,137,135,134,133,132,
130,129,128,127,125,124,123,122,120,119,118,117,116,114,113,112,111,110,109,107,
106,105,104,103,102,101,99,98,97,96,95,94,93,92,91,90,89,88,86,85,
84,83,82,81,80,79,78,77,76,75,74,73,72,71,71,70,69,68,67,66,
65,64,63,62,61,60,60,59,58,57,56,55,54,54,53,52,51,50,50,49,
48,47,46,46,45,44,43,43,42,41,40,40,39,38,37,37,36,35,35,34,
33,33,32,31,31,30,30,29,28,28,27,27,26,25,25,24,24,23,23,22,
21,21,20,20,19,19,18,18,17,17,16,16,16,15,15,14,14,13,13,12,
12,12,11,11,11,10,10,9,9,9,8,8,8,7,7,7,7,6,6,6,
5,5,5,5,4,4,4,4,3,3,3,3,3,2,2,2,2,2,2,1,
1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,
1,1,2,2,2,2,2,2,3,3,3,3,3,4,4,4,4,5,5,5,
5,6,6,6,7,7,7,7,8,8,8,9,9,9,10,10,11,11,11,12,
12,12,13,13,14,14,15,15,16,16,16,17,17,18,18,19,19,20,20,21,
21,22,23,23,24,24,25,25,26,27,27,28,28,29,30,30,31,31,32,33,
33,34,35,35,36,37,37,38,39,40,40,41,42,43,43,44,45,46,46,47,
48,49,50,50,51,52,53,54,54,55,56,57,58,59,60,60,61,62,63,64,
65,66,67,68,69,70,71,71,72,73,74,75,76,77,78,79,80,81,82,83,
84,85,86,88,89,90,91,92,93,94,95,96,97,98,99,101,102,103,104,105,
106,107,109,110,111,112,113,114,116,117,118,119,120,122,123,124,125,127,128,129,
130,132,133,134,135,137,138,139,141,142,143,145,146,147,149,150,151,153,154,155,
157,158,159,161,162,164,165,166,168,169,171,172,173,175,176,178,179,181,182,184,
185,186,188,189,191,192,194,195,197,198,200,201,203,204,206,208,209,211,212,214,
215,217,218,220,222,223,225,226,228,230,231,233,234,236,238,239,241,243,244,246,
247,249,251,252,254,256,257,259,261,262,264,266,268,269,271,273,274,276,278,280,
281,283,285,287,288,290,292,294,295,297,299,301,302,304,306,308,310,311,313,315,
317,319,320,322,324,326,328,330,331,333,335,337,339,341,342,344,346,348,350,352,
354,356,357,359,361,363,365,367,369,371,373,375,376,378,380,382,384,386,388,390,
392,394,396,398,400,402,404,406,408,409,411,413,415,417,419,421,423,425,427,429,
431,433,435,437,439,441,443,445,447,449,451,453,455,457,459,461,463,465,468,470,
472,474,476,478,480,482,484,486,488,490,492,494,496,498,500,502,504,507,509,511,
513,515,517,519,521,523,525,527,529,532,534,536,538,540,542,544,546,548,550,553,
555,557,559,561,563,565,567,569,572,574,576,578,580,582,584,586,588,591,593,595,
597,599,601,603,605,608,610,612,614,616,618,620,623,625,627,629,631,633,635,638,
640,642,644,646,648,650,652,655,657,659,661,663,665,667,670,672,674,676,678,680
};
Actual waveforms
Add offset
MySine2000[cntr] = MySine2000[cntr] + 682;
Sine 10k, DMA is 2MSPS (500nS)
const uint32_t MySine200[] =
{
683,704,725,747,768,789,810,831,852,873,893,914,934,954,973,992,1011,1030,1048,1066,
1084,1101,1118,1134,1150,1165,1180,1194,1208,1222,1235,1247,1259,1270,1281,1291,1300,1309,1317,1325,
1332,1338,1344,1349,1353,1357,1360,1362,1364,1365,1365,1365,1364,1362,1360,1357,1353,1349,1344,1338,
1332,1325,1317,1309,1300,1291,1281,1270,1259,1247,1235,1222,1208,1194,1180,1165,1150,1134,1118,1101,
1084,1066,1048,1030,1011,992,973,954,934,914,893,873,852,831,810,789,768,747,725,704,
683,661,640,618,597,576,555,534,513,492,472,451,431,411,392,373,354,335,317,299,
281,264,247,231,215,200,185,171,157,143,130,118,106,95,84,74,65,56,48,40,
33,27,21,16,12,8,5,3,1,0,0,0,1,3,5,8,12,16,21,27,
33,40,48,56,65,74,84,95,106,118,130,143,157,171,185,200,215,231,247,264,
281,299,317,335,354,373,392,411,431,451,472,492,513,534,555,576,597,618,640,661
};
Actual waveform
Add together
MySine2000[cntr] = MySine2000[cntr] + MySine200[cntr % MySine200_SIZE];
It is still ok to use HAL instead of LL because the codes will be used only during init. Problem is when you want to change the waveform on the fly
void DMA1_Channel1_IRQHandler(void)
{
/* USER CODE BEGIN DMA1_Channel1_IRQn 0 */
GPIOC->BSRR = (1<<(8));
/* USER CODE END DMA1_Channel1_IRQn 0 */
HAL_DMA_IRQHandler(&hdma_dac3_ch1);
/* USER CODE BEGIN DMA1_Channel1_IRQn 1 */
GPIOC->BSRR = (1<<(8+16));
/* USER CODE END DMA1_Channel1_IRQn 1 */
}
1.13uS Duration
970nS Duration
void HAL_DAC_ConvCpltCallbackCh1(DAC_HandleTypeDef *hdac)
{
/* Prevent unused argument(s) compilation warning */
UNUSED(hdac);
/* NOTE : This function should not be modified, when the callback is needed,
the HAL_DAC_ConvCpltCallbackCh1 could be implemented in the user file
*/
GPIOC->BSRR = (1<<(8));
}
void HAL_DAC_ConvHalfCpltCallbackCh1(DAC_HandleTypeDef *hdac)
{
/* Prevent unused argument(s) compilation warning */
UNUSED(hdac);
/* NOTE : This function should not be modified, when the callback is needed,
the HAL_DAC_ConvHalfCpltCallbackCh1 could be implemented in the user file
*/
GPIOC->BSRR = (1<<(8+16));
}
GPIOC->BSRR = (1<<(8));
/*##- Enable DAC Channel and associated DMA ##############################*/
if(HAL_OK != HAL_DAC_Start_DMA(&hdac3, DAC_CHANNEL_1,
(uint32_t*)MySine2000, MySine2000_SIZE, DAC_ALIGN_12B_R))
{
/* Start DMA Error */
Error_Handler();
}
GPIOC->BSRR = (1<<(8+16));
As shown, we cannot use HAL_DAC_Start_DMA every time we need to change the waveform on the fly due to very long duration of 1.25ms. As our DAC speed is 2MHz! or 500nS!
HAL_DAC_Start_DMA (stm32g4xx_hal_dac.c) > HAL_DMA_Start_IT (stm32g4xx_hal_dma.c) > DMA_SetConfig
DMA_SetConfig(DMA_HandleTypeDef *hdma, uint32_t SrcAddress, uint32_t DstAddress, uint32_t DataLength)
where:
*hdma = hdac3->DMA_Handle1
SrcAddress = MySine2000 / MySine4000
DstAddress = (uint32_t)&hdac->Instance->DHR12R2 (DAC_ALIGN_12B_R/DHR12R2)
DataLength = MySine2000/MySine4000_SIZE
inside DMA_SetConfig is
/* Configure DMA Channel source address */
hdma->Instance->CPAR = SrcAddress;
in my case
hdma_dac3_ch1.Instance->CMAR = MySine4000; // or MySine2000
void HAL_DAC_ConvCpltCallbackCh1(DAC_HandleTypeDef *hdac)
{
/* Prevent unused argument(s) compilation warning */
UNUSED(hdac);
hdma_dac3_ch1.Instance->CMAR = MySine4000;
}
void HAL_DAC_ConvHalfCpltCallbackCh1(DAC_HandleTypeDef *hdac)
{
/* Prevent unused argument(s) compilation warning */
UNUSED(hdac);
hdma_dac3_ch1.Instance->CMAR = MySine2000;
}
136nS Duration
276nS Duration
From previous project where we checked how fast the DAC can achieve from minimum to maximum transition, we had around 4.74Mhz! Of course that is worst case, but for this test, we will be using sinewave and the transition will not be as worse.
Now we use Sine12bit for a more coarse sine wave to observe the DAC steps better.
Sine12bit running at 2Mhz/2MSPS
We can try til 14.7Mhz/MSPS
But is it now acting erratic
It is now due to DMA interrupt, so we disable it and run til around 17Mhz/MSPS
With 32sample points and TIM6 running @ 170Mhz/(5 X 2), we have a freq of the Sine12bit as 532kHz as shown
Some abnormal reaction if we increase further 17Mhz/MSPS, like 4.2Mhz/MSPS for TIM6 = 170Mhz/(2 X 2), the 32sample of the sine have different freq
Investigate when TIM6 or DAC is more than 17Mhz/MSPS
Troubleshooting HRTIM internal trigger
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