STM32F7: use of DMA to change CCR1 of timer gives transfer error

[andre239955_st]

Posted on July 08, 2016 at 08:11

Hi all,

I use DMA and linked timers in most of my projects with no problems on STM32F1 and STM32F4. I want to do the same on the STM32F7. As a test I want to use a DMA stream to create a changing signal on a PWM output. When I debug the code I see that the DMA has a transfer error but I don't understand why. Here is my initialisation code (which with some minor changes works on STM32F1):            RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA1, ENABLE);                      DMA_Cmd(DMA1_Stream7, DISABLE);                        DMA_DeInit(DMA1_Stream7);            DMA_InitStruct.DMA_Channel = DMA_Channel_3;            DMA_InitStruct.DMA_PeripheralBaseAddr = (uint32_t)(&(TIM10->CCR1));            DMA_InitStruct.DMA_Memory0BaseAddr = (uint32_t)&sintab_wa;            DMA_InitStruct.DMA_DIR = DMA_DIR_MemoryToPeripheral;            DMA_InitStruct.DMA_BufferSize = (uint32_t)nsamp_;            DMA_InitStruct.DMA_PeripheralInc = DMA_PeripheralInc_Disable;            DMA_InitStruct.DMA_MemoryInc = DMA_MemoryInc_Enable;            DMA_InitStruct.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;            DMA_InitStruct.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;            DMA_InitStruct.DMA_Mode = DMA_Mode_Circular;            DMA_InitStruct.DMA_Priority = DMA_Priority_High;            DMA_InitStruct.DMA_FIFOMode = DMA_FIFOMode_Disable;            DMA_InitStruct.DMA_FIFOThreshold = DMA_FIFOThreshold_1QuarterFull;            DMA_InitStruct.DMA_MemoryBurst = DMA_MemoryBurst_Single;            DMA_InitStruct.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;                        /* Wait for  DMA_GetCmdStatus() */                        while(DMA_GetCmdStatus(DMA1_Stream7) != DISABLE)            {}                        /* Flush cashes to memory and wait for flush to complete */            SCB_CleanDCache();                          DMA_Init(DMA1_Stream7, &DMA_InitStruct);                          /* Enable DMA1 channel3 */            DMA_Cmd(DMA1_Stream7, ENABLE);I have both instruction and data cache enabled, is that what's blocking? Can anyone give me some clue why I get the bus error?Thanks,Andre #stm32f7-dma-timer

[waclawek.jan]

Posted on July 08, 2016 at 08:37

Where is sintab_wa located?

Note, that in 'F7, ITCM-mapped memories (i.e. at addresses 00000000-07FFFFFF) are private to the processor and are not accessible from the bus matrix (including DMA). See AN4667 and the ARM Cortex-M7 TRM. JW

[Tesla DeLorean]

Posted on July 08, 2016 at 08:42

Wouldn't TIM10 need to be on DMA2?

Not seeing any TIM10 trigger source in RM0410The F3 errors if trying to DMA from ROMThe F4 errors if trying to DMA from CCMConfirm memory address, and routability.

[andre239955_st]

Posted on July 08, 2016 at 08:50

sintab_wa is located in RAM (0x2001414C). I use TIM2 on DMA1 for the request (stream 7 channel 3) but I update TIM10->CCR1 with the new value from sintab_wa. Yes, I like to hookup things as much as possible :)

[waclawek.jan]

Posted on July 08, 2016 at 09:11

Post the relevant DMA registers' content.

JW

[andre239955_st]

Posted on July 08, 2016 at 10:27

Ok, here we go:

AR.

[andre239955_st]

Posted on July 08, 2016 at 10:34

I just made a small change: instead of reprogramming TIM10->CCR1 I used TIM2->CCR1. This one works... So I tried using a different timer, TIM5. This is also working. So it seems that I am not allowed to use TIM10's CCR1 as destination? Extremely strange...

AR

[andre239955_st]

Posted on July 08, 2016 at 10:48

More testing done. I have discovered that it only works with some timers:

TIM2, TIM3, TIM4, TIM5, TIM12, TIM13 and TIM14. All the other timers generate the error! I guess ST has some digging to do...AR

[Tesla DeLorean]

Posted on July 08, 2016 at 11:39

TIM2, TIM3, TIM4, TIM5, TIM12, TIM13 and TIM14. All the other timers generate the error! I guess ST has some digging to do...

Which are all, unsurprisingly, on APB1...