Generating sine wave on STM32F3 with DMA - garbled output

Question

I am trying to generate a waveform using a const table, DMA and DAC.

This is the STM32F303VCT on a Discovery F3 board.

I am using libopencm3, but I hope you'll clearly see what is happening - it's all just functions to set the control registers.

#define SINE_TABLE_LEN 256

static const uint16_t sine_table[] = {
    2047, 2097, 2147, 2198, 2248, 2298, 2347, 2397, 2446, 2496, 2544, 2593, 2641, 2689, 2737, 2784, 2830, 2877, 2922, 2967, 3012, 3056, 3099, 3142, 3184, 3226, 3266, 3306, 3346, 3384, 3422, 3458, 3494, 3530, 3564, 3597, 3629, 3661, 3691, 3721, 3749, 3776, 3803, 3828, 3852, 3875, 3897, 3918, 3938, 3957, 3974, 3991, 4006, 4020, 4033, 4044, 4055, 4064, 4072, 4079, 4084, 4088, 4092, 4093, 4094, 4093, 4092, 4088, 4084, 4079, 4072, 4064, 4055, 4044, 4033, 4020, 4006, 3991, 3974, 3957, 3938, 3918, 3897, 3875, 3852, 3828, 3803, 3776, 3749, 3721, 3691, 3661, 3629, 3597, 3564, 3530, 3494, 3458, 3422, 3384, 3346, 3306, 3266, 3226, 3184, 3142, 3099, 3056, 3012, 2967, 2922, 2877, 2830, 2784, 2737, 2689, 2641, 2593, 2544, 2496, 2446, 2397, 2347, 2298, 2248, 2198, 2147, 2097, 2047, 1997, 1947, 1896, 1846, 1796, 1747, 1697, 1648, 1598, 1550, 1501, 1453, 1405, 1357, 1310, 1264, 1217, 1172, 1127, 1082, 1038, 995, 952, 910, 868, 828, 788, 748, 710, 672, 636, 600, 564, 530, 497, 465, 433, 403, 373, 345, 318, 291, 266, 242, 219, 197, 176, 156, 137, 120, 103, 88, 74, 61, 50, 39, 30, 22, 15, 10, 6, 2, 1, 0, 1, 2, 6, 10, 15, 22, 30, 39, 50, 61, 74, 88, 103, 120, 137, 156, 176, 197, 219, 242, 266, 291, 318, 345, 373, 403, 433, 465, 497, 530, 564, 600, 636, 672, 710, 748, 788, 828, 868, 910, 952, 995, 1038, 1082, 1127, 1172, 1217, 1264, 1310, 1357, 1405, 1453, 1501, 1550, 1598, 1648, 1697, 1747, 1796, 1846, 1896, 1947, 1997
//  0, 16, 32, 48, 64, 80, 96, 112, 128, 144, 160, 176, 192, 208, 224, 240, 256, 272, 288, 304, 320, 336, 352, 368, 384, 400, 416, 432, 448, 464, 480, 496, 512, 528, 544, 560, 576, 592, 608, 624, 640, 656, 672, 688, 704, 720, 736, 752, 768, 784, 800, 816, 832, 848, 864, 880, 896, 912, 928, 944, 960, 976, 992, 1008, 1024, 1040, 1056, 1072, 1088, 1104, 1120, 1136, 1152, 1168, 1184, 1200, 1216, 1232, 1248, 1264, 1280, 1296, 1312, 1328, 1344, 1360, 1376, 1392, 1408, 1424, 1440, 1456, 1472, 1488, 1504, 1520, 1536, 1552, 1568, 1584, 1600, 1616, 1632, 1648, 1664, 1680, 1696, 1712, 1728, 1744, 1760, 1776, 1792, 1808, 1824, 1840, 1856, 1872, 1888, 1904, 1920, 1936, 1952, 1968, 1984, 2000, 2016, 2032, 2048, 2063, 2079, 2095, 2111, 2127, 2143, 2159, 2175, 2191, 2207, 2223, 2239, 2255, 2271, 2287, 2303, 2319, 2335, 2351, 2367, 2383, 2399, 2415, 2431, 2447, 2463, 2479, 2495, 2511, 2527, 2543, 2559, 2575, 2591, 2607, 2623, 2639, 2655, 2671, 2687, 2703, 2719, 2735, 2751, 2767, 2783, 2799, 2815, 2831, 2847, 2863, 2879, 2895, 2911, 2927, 2943, 2959, 2975, 2991, 3007, 3023, 3039, 3055, 3071, 3087, 3103, 3119, 3135, 3151, 3167, 3183, 3199, 3215, 3231, 3247, 3263, 3279, 3295, 3311, 3327, 3343, 3359, 3375, 3391, 3407, 3423, 3439, 3455, 3471, 3487, 3503, 3519, 3535, 3551, 3567, 3583, 3599, 3615, 3631, 3647, 3663, 3679, 3695, 3711, 3727, 3743, 3759, 3775, 3791, 3807, 3823, 3839, 3855, 3871, 3887, 3903, 3919, 3935, 3951, 3967, 3983, 3999, 4015, 4031, 4047, 4063, 4079
};    

void send_dac_sine()
{
    const uint32_t dma = DMA2;
    const uint32_t ch = DMA_CHANNEL3;

    dac_dma_disable(CHANNEL_1);
    dma_disable_channel(dma, ch);
    dma_channel_reset(dma, ch);

    // DMA config
    dma_enable_circular_mode(dma, ch);

    dma_set_peripheral_address(dma, ch, (uint32_t) &DAC_DHR12R1);
    dma_set_memory_address(dma, ch, (uint32_t) sine_table);

    dma_set_memory_size(dma, ch, DMA_CCR_MSIZE_16BIT); // uint16_t
    dma_set_peripheral_size(dma, ch, DMA_CCR_MSIZE_32BIT); // 32-bit register
    dma_set_number_of_data(dma, ch, SINE_TABLE_LEN);
    dma_enable_memory_increment_mode(dma, ch); // incr mem. addr
    dma_disable_peripheral_increment_mode(dma, ch); // keep periph addr
    dma_set_read_from_memory(dma, ch); // memory -> periph

    dma_set_priority(dma, ch, DMA_CCR_PL_VERY_HIGH);

    // launch

    dac_dma_enable(CHANNEL_1); // enable the DAC to send DMA requests
    dma_enable_channel(dma, ch);
}

The DAC is triggered by TIMER6 TRGO.

I think I must have some bug in the table definition or the table memory address.

The DMA is running, I can see something sent to the DAC.

However, it is not my table - here's it plotted, as captured by an ADC:

What could be wrong?

ps. if I let it run longer, I get something this (it's periodic)

I'd appreciate if you helped or gave suggestions, rather than casting close votes. — MightyPork, Oct 30 '15 at 17:50
The "reality" graph does resemble a sine wave, but too chunky. The newest example at the bottom looks as though it is trying but getting restarted. Timing issues? — Weather Vane, Oct 30 '15 at 17:57
Sorry for the confusion with the graphs, the bottom one is actually captured when it was sending the second table - linear 0..4095. Doesn't make much sense tbh. I think it is reading a different part of the memory... — MightyPork, Oct 30 '15 at 18:00
but it already is `(uint32_t*)`. The function takes `uint32_t` - absolute address. It is `8006d42`, and when I checked the disassembly, the table is there all right... — MightyPork, Oct 30 '15 at 18:11
yea that's what I meant. Result the same if I change it, though - only change is I get compiler warnings — MightyPork, Oct 30 '15 at 18:13

score 3 · Answer 1 · answered Oct 30 '15 at 20:54

The whole problem was one wrong letter in a constant identifier. Duuuh

Peripheral size is specified with DMA_CCR_PSIZE_*, not DMA_CCR_MSIZE_*.

Also I messed up the pointers / addresses...

Full, working code:

#define SINE_TABLE_LEN 256
const uint16_t sine_table[SINE_TABLE_LEN] = { // now with actual sine
    2047, 2097, 2147, 2198, 2248, 2298, 2347, 2397, 2446, 2496, 2544, 2593, 2641, 2689, 2737, 2784, 2830, 2877, 2922, 2967, 3012, 3056, 3099, 3142, 3184, 3226, 3266, 3306, 3346, 3384, 3422, 3458, 3494, 3530, 3564, 3597, 3629, 3661, 3691, 3721, 3749, 3776, 3803, 3828, 3852, 3875, 3897, 3918, 3938, 3957, 3974, 3991, 4006, 4020, 4033, 4044, 4055, 4064, 4072, 4079, 4084, 4088, 4092, 4093, 4094, 4093, 4092, 4088, 4084, 4079, 4072, 4064, 4055, 4044, 4033, 4020, 4006, 3991, 3974, 3957, 3938, 3918, 3897, 3875, 3852, 3828, 3803, 3776, 3749, 3721, 3691, 3661, 3629, 3597, 3564, 3530, 3494, 3458, 3422, 3384, 3346, 3306, 3266, 3226, 3184, 3142, 3099, 3056, 3012, 2967, 2922, 2877, 2830, 2784, 2737, 2689, 2641, 2593, 2544, 2496, 2446, 2397, 2347, 2298, 2248, 2198, 2147, 2097, 2047, 1997, 1947, 1896, 1846, 1796, 1747, 1697, 1648, 1598, 1550, 1501, 1453, 1405, 1357, 1310, 1264, 1217, 1172, 1127, 1082, 1038, 995, 952, 910, 868, 828, 788, 748, 710, 672, 636, 600, 564, 530, 497, 465, 433, 403, 373, 345, 318, 291, 266, 242, 219, 197, 176, 156, 137, 120, 103, 88, 74, 61, 50, 39, 30, 22, 15, 10, 6, 2, 1, 0, 1, 2, 6, 10, 15, 22, 30, 39, 50, 61, 74, 88, 103, 120, 137, 156, 176, 197, 219, 242, 266, 291, 318, 345, 373, 403, 433, 465, 497, 530, 564, 600, 636, 672, 710, 748, 788, 828, 868, 910, 952, 995, 1038, 1082, 1127, 1172, 1217, 1264, 1310, 1357, 1405, 1453, 1501, 1550, 1598, 1648, 1697, 1747, 1796, 1846, 1896, 1947, 1997
};

void send_dac_sine()
{
    const uint32_t dma = DMA2;
    const uint32_t ch = DMA_CHANNEL3;

    dac_set_waveform_generation(DAC_CR_WAVE1_DIS);
    dac_dma_disable(CHANNEL_1);
    dma_disable_channel(dma, ch);
    dma_channel_reset(dma, ch);

    dma_enable_circular_mode(dma, ch);
    dma_set_peripheral_address(dma, ch, (uint32_t) &DAC_DHR12R1);
    dma_set_memory_address(dma, ch, (uint32_t) &sine_table);
    dma_set_memory_size(dma, ch, DMA_CCR_MSIZE_16BIT);
    dma_set_peripheral_size(dma, ch, DMA_CCR_PSIZE_16BIT);
    dma_set_read_from_memory(dma, ch);
    dma_set_number_of_data(dma, ch, SINE_TABLE_LEN);

    dma_set_priority(dma, ch, DMA_CCR_PL_VERY_HIGH);

    dma_enable_memory_increment_mode(dma, ch);
    dma_disable_peripheral_increment_mode(dma, ch);

    dac_dma_enable(CHANNEL_1);
    dma_enable_channel(dma, ch);
}

I tried configuring the timer and GPIO needed to get your code running, but failed. I am using a STM32F3-DISCOVERY board. Maybe you have an idea what is wrong. https://gist.github.com/ReneHollander/7cebb2581fb7d3c13ba70f540f58acc6 Edit: I forgot to add that only the blinky leds are working. I just put it in to see if the code actually runs. And obviously I am using TIM2, but it should be configured correctly. — Rene8888, Dec 19 '16 at 21:56

score 1 · Answer 2 · answered Oct 30 '15 at 18:53

1

have you tried to memcpy it somewhere? it might have something to do with it being static, ie. not on the normal stack. just a thought...

answered Oct 30 '15 at 18:53

David van rijn

2,108
9
21

Thanks, but that isn't it. I tried sending it over USART, and it is OK – MightyPork Oct 30 '15 at 19:28
I got somewhere - it is counting OK, but sends: 8x first 16 numbers, then 8x last 16 numbers. It is just weird. And the table is there in the memory, just as it should be... hardware fault? – MightyPork Oct 30 '15 at 19:39

Generating sine wave on STM32F3 with DMA - garbled output

2 Answers2