APM32F030CC6T USART1 DMA channel remap issue

cifron

Hello. I am using an APM32F030CC6T controller and according to the documentation you provided I am trying to remap the DMA channels of USART1 from 2 and 3 to 4 and 5. But I still can’t get it to work. I spent a week trying and all were unsuccessful. I would like you to guide me whether this remap is implemented in this controller and whether I should continue wasting my time or whether it is not implemented and there is no point in trying. In the standard library there is an example for remapping the DMA channel of the receiver. I programmed it as a test in the controller but it also does not work. My question is whether this function is implemented in the controller or not?
I am talking about remapping the DMA channels and not about remapping the GPIO

cifron

Won’t some engineer from GEEHY pay attention to the question and answer?

Yang Chao

Dear Cifron,

I’m sorry for the late reply and letting you working on this matter for weeks.

I’m using the APM32F0xx_SDK_V1.8.4 as the standard peripheral library, within the SDK you can find the example “DMA\DMA_Usart”, the USART1 initiation (which is configured before DMA1_CH4_5 enabling and NVIC configuration) includes using SYSCFG on APB2 to remap the DMA channel.

Please find the codes below:

From USART1_Init()

   /* Enable SYSCFG Clock for Remaping DMA Channel*/
    RCM_EnableAPB2PeriphClock(RCM_APB2_PERIPH_SYSCFG);
    /* Remap USART1_RX Channel to DMA channel 5*/
    SYSCFG_EnableDMAChannelRemap(SYSCFG_DAM_REMAP_USART1RX);

From DMA_RX_Init(), the initiation of DMA_TX shall be similar

/* Enable DMA clock */
    RCM_EnableAHBPeriphClock(RCM_AHB_PERIPH_DMA1);
    /* DMA Configure */
    DMA_Config_T dmaConfig;
    /* size of buffer*/
    dmaConfig.bufferSize = BufSize;
    /* set memory Data Size*/
    dmaConfig.memoryDataSize = DMA_MEMORY_DATASIZE_BYTE;
    /* Set peripheral Data Size*/
    dmaConfig.peripheralDataSize = DMA_PERIPHERAL_DATASIZE_BYTE;
    /* Enable Memory Address increase*/
    dmaConfig.memoryInc = DMA_MEMORY_INC_ENABLE;
    /* Disable Peripheral Address increase*/
    dmaConfig.peripheralInc = DMA_PERIPHERAL_INC_DISABLE;
    /* Reset Circular Mode*/
    dmaConfig.circular = DMA_CIRCULAR_DISABLE;
    /* Disable M2M*/
    dmaConfig.memoryTomemory = DMA_M2M_DISABLE;
    /* set priority*/
    dmaConfig.priority = DMA_PRIORITY_LEVEL_HIGHT;
    /* read from memory*/
    dmaConfig.direction = DMA_DIR_PERIPHERAL;
    /* Set memory Address*/
    dmaConfig.memoryAddress = (uint32_t)RxBuf;
    /* Set Peripheral Address*/
    dmaConfig.peripheralAddress = (uint32_t)&USART1->RXDATA;

    DMA_Config(DMA1_CHANNEL_5, &dmaConfig);
    /* Clear DMA TF flag*/
    DMA_ClearIntFlag(DMA1_INT_FLAG_TF5);
    /* Enable DMA Interrupt*/
    DMA_EnableInterrupt(DMA1_CHANNEL_5, DMA_INT_TFIE);

#if defined (APM32F030)
    NVIC_EnableIRQRequest(DMA1_CH4_5_IRQn, 2);
    USART_ClearStatusFlag(USART1, USART_FLAG_TXC);

    DMA_Enable(DMA1_CHANNEL_5);

From DMA_Isr() //The playback function of DMA1_CH4_5_IRQHandler()

if (DMA_ReadStatusFlag(DMA1_FLAG_TF5))
    {
        /* do something*/
        DMA_ClearStatusFlag(DMA1_FLAG_TF5);
    }

From main()

USART1_Init();

    /* Config channel5 of DMA */
    DMA_Disable(DMA1_CHANNEL_5);

    DMA_Rx_Init((uint32_t*)DMA_USART_RxBuf);

    USART_EnableDMA(USART1, USART_DMA_REQUEST_RX);

The function SYSCFG_EnableDMAChannelRemap() requires parameter as uint32_t channel: SYSCFG_DAM_REMAP_USART1TX, SYSCFG_DAM_REMAP_USART1RX.

Here’s the introduction to the registers that are related to the remap of DMA channels:

Geehy

Dear cifron,
Please accept our sincere apologies for the delay in responding to your inquiry. We understand your frustration regarding the time spent debugging this issue.

We have reviewed the thread, and I can confirm that the solution provided above is correct regarding the DMA remapping mechanism on the APM32F030.
We are also reviewing our documentation to ensure this remap procedure is described more clearly to prevent other developers from facing the same difficulty.

If you still encounter any issues, please feel free to reply to this thread or contact us directly at
https://ding.cjfx.cn/f/e6nawgpp?e_field=%E5%BC%80%E5%8F%91%E8%80%85%E7%A4%BE%E5%8C%BA.

Our FAE team will continue to follow up to ensure your problem is fully resolved.

cifron

Thanks for the answer and help. I managed to do it and remap the DMA channel on USART1. And of course before writing to you I reviewed the examples in SDK 1.8.3. What misled me was that the remap function you used there was:
void SYSCFG_EnableDMAChannelRemap(uint32_t channel)
{
SYSCFG->CFG1 |= (uint32_t)channel;
}
And in fact the real remap is done with
void DMA_ConfigRemap(DMA_T* dma, DMA_CHANNEL_REMAP_T remap)
{
dma->CHSEL &= ~((uint32_t)0×0F « (uint32_t)(remap » 28) * 4);
dma->CHSEL |= (uint32_t)(remap & 0×0FFFFFFFF);
}
Anyway, I managed it. Thank you for your cooperation.

Yang Chao

cifron
Hi Cifron. Yes, I am just logging into the community to discuss this detail with you.

I have noted that DMA Request Table 1 and the SYSCFG remapping are restricted to the APM32F030×4×6×8 series.

The APM32F030xC exclusively follows the second DMA mapping table. It utilizes the CHSELx register within each channel to configure different DMA remaps.

This design choice is due to the fact that the APM32F030xC offers significantly more peripheral resources compared to the F030×4×6×8 series.