I've been scratching my head for the past few days as I try to
understand why and what is going on... So here it goes:
Current config: stm32f407VG (same as stm32f4 discovery)
I set up a project using the default linker and startup files from
www.onarm.com.
Init the ADC & DMA's
1 | ADC_CommonInitStructure.ADC_Mode = ADC_DualMode_RegSimult;
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2 | ADC_CommonInitStructure.ADC_Prescaler = ADC_Prescaler_Div2;
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3 | ADC_CommonInitStructure.ADC_DMAAccessMode = ADC_DMAAccessMode_1;
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4 |
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5 | DMA_InitTypeDef DMA_InitStructure;
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6 | NVIC_InitTypeDef NVIC_InitStructure;
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7 |
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8 | DMA_InitStructure.DMA_Channel = DMA_Channel_0;
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9 | DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t) &RawADCData.adcRaw1;
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10 | DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t) ADC_CCR_ADDRESS;
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11 | DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory;
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12 | DMA_InitStructure.DMA_BufferSize = ADC_SAMPLE_NUM * ADC_NUM * ADC_BUFFER_MULTIPLIER;
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13 | DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
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14 | DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
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15 | DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
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16 | DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
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17 | DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
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18 | DMA_InitStructure.DMA_Priority = DMA_Priority_High;
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19 | DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Enable;
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20 | DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull;
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21 | DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;
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22 | DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
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23 | DMA_Init(DMA2_Stream0, &DMA_InitStructure);
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24 |
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25 | /*Interrupt when half of DMA is done, so we do not overwrite our values when processing*/
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26 | DMA_ITConfig(DMA2_Stream0, DMA_IT_HT | DMA_IT_TC, ENABLE);
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27 | DMA_ClearITPendingBit(DMA2_Stream0, DMA_IT_TEIF0 | DMA_IT_DMEIF0 | DMA_IT_FEIF0 | DMA_IT_TCIF0 | DMA_IT_HTIF0);
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28 |
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29 | // Enable the DMA2_Stream0 global Interrupt
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30 | NVIC_InitStructure.NVIC_IRQChannel = DMA2_Stream0_IRQn;
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31 | NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
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32 | NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
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33 | NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
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34 | NVIC_Init(&NVIC_InitStructure);
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35 |
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36 | /* DMA2_Stream0 enable */
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37 | DMA_Cmd(DMA2_Stream0, ENABLE);
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--Symptom A:
Compile on GCC with CooCox as IDE, the DMA values are all garbled, after
looking at the memory, it seems like the DMA values were sometimes
offset by 1 word.
--Symptom B: Floats do not print correctly, printf works, but they are
not passed on VA_ARGS correctly, offset by x bytes, x is pretty random.
--Sympton C: I add a struct into my file somewhere, say
1 | struct b
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2 | {
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3 | float z[40];
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4 | }
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Everything begins to work, prints are correct, DMA is correct.
I add anther struct into anther file
1 | struct b
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2 | {
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3 | float z[80];
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4 | int z[3];
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5 | }
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DMA is correct, but printf does not work again. If i twitter around with
the structs, DMA can be broken, but printf works, or they all can be
broken.
I have a feeling that it is a linker error or alignment error, but do
not know where else to look.
The entire codebase is here
(http://code.google.com/p/narwhalroboticsquad/source/browse/?r=25#svn%2Ftrunk%2FNarwhalQuad)
if you are curious, built with Coocox IDE with the GNU ARM toolchain.
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