DMA and SSP1

[hamouz]

Posted on November 25, 2011 at 14:45

I would like to use DMA with SSP1. There is a problem that when flow control is set to peripheral, data are transfered, but I am not able to control how many bytes are transfered. If I change flow control to DMA, nothing happens. Any single transfer doesn't occur, although both single and burst requests are signaled (registers DMA_SSBR and DMA_SBRR).

I can't find where is the error. I believe I did my best according to documentation. In previous topics there was an example (Example of DMA and SSP, 11/9/2006 2:10 AM), but the attachment is lost and no longer available. Eris, can you post it again? Tomas My code: ============================================================== #define    SPI_SD               SSP1 #define    DMA_CHANNEL_RX       DMA_Channel4 #define    DMA_CHANNEL_TX       DMA_Channel5 #define    DMA_CHANNEL_RX_IDX   Channel4 void str91_dma_transfer_receive( const BYTE *buff, UINT count) {     DMA_InitTypeDef         DMA_InitStructure;     WORD rw_workbyte[] = { 0xffff };     DMA_DeInit();     DMA_Cmd(ENABLE);     // shared DMA configuration values     DMA_InitStructure.DMA_Channel_LLstItm = 0;     DMA_InitStructure.DMA_Channel_DesWidth = DMA_DesWidth_Byte;     DMA_InitStructure.DMA_Channel_SrcWidth = DMA_SrcWidth_Byte;     DMA_InitStructure.DMA_Channel_DesBstSize = DMA_DesBst_1Data;     DMA_InitStructure.DMA_Channel_SrcBstSize = DMA_SrcBst_1Data;     DMA_InitStructure.DMA_Channel_TrsfSize = count;     // RX - storing data in buffer     DMA_InitStructure.DMA_Channel_SrcAdd = (DWORD)(&SPI_SD->DR);     DMA_InitStructure.DMA_Channel_DesAdd = (DWORD)buff; //        DMA_InitStructure.DMA_Channel_FlowCntrl = DMA_FlowCntrl2_DMA;  // peripheral_to_memory / DMA     DMA_InitStructure.DMA_Channel_FlowCntrl = DMA_FlowCntrl_Perip2;  // peripheral_to_memory / SSP     DMA_InitStructure.DMA_Channel_Src = DMA_SRC_SSP1_RX;     DMA_InitStructure.DMA_Channel_Des = 0;     DMA_Init(DMA_CHANNEL_RX, &DMA_InitStructure);     DMA_ChannelSRCIncConfig(DMA_CHANNEL_RX, DISABLE);     DMA_ChannelDESIncConfig(DMA_CHANNEL_RX, ENABLE);          // TX - must send 0xFF     DMA_InitStructure.DMA_Channel_SrcAdd = (DWORD)rw_workbyte;     DMA_InitStructure.DMA_Channel_DesAdd = (DWORD)(&SPI_SD->DR); //        DMA_InitStructure.DMA_Channel_FlowCntrl = DMA_FlowCntrl1_DMA;  // memory_to_peripheral / DMA     DMA_InitStructure.DMA_Channel_FlowCntrl = DMA_FlowCntrl_Perip1;  // memory_to_peripheral / SSP     DMA_InitStructure.DMA_Channel_Src = 0;     DMA_InitStructure.DMA_Channel_Des = DMA_DES_SSP1_TX;     DMA_Init(DMA_CHANNEL_TX, &DMA_InitStructure);     DMA_ChannelSRCIncConfig(DMA_CHANNEL_TX, DISABLE);     DMA_ChannelDESIncConfig(DMA_CHANNEL_TX, DISABLE);       // reusing the same data in memory     // enable interrupts     DMA_ITConfig(DMA_CHANNEL_RX, ENABLE);     DMA_ITConfig(DMA_CHANNEL_TX, ENABLE);     DMA_ITMaskConfig(DMA_CHANNEL_RX, DMA_ITMask_ITC, ENABLE);     DMA_ITMaskConfig(DMA_CHANNEL_TX, DMA_ITMask_ITC, ENABLE);     // Enable  TX/RX request in SSP controller     SSP_DMACmd(SPI_SD, SSP_DMA_Receive, ENABLE);     SSP_DMACmd(SPI_SD, SSP_DMA_Transmit, ENABLE);          // Enable DMA channels     DMA_ChannelCmd(DMA_CHANNEL_RX, ENABLE);     DMA_ChannelCmd(DMA_CHANNEL_TX, ENABLE);     // wait for end of transfer     while (DMA_GetITStatus(DMA_CHANNEL_RX_IDX, DMA_TCRS) == RESET);     // Disable DMA channels     DMA_ChannelCmd(DMA_CHANNEL_RX, DISABLE);     DMA_ChannelCmd(DMA_CHANNEL_TX, DISABLE);     // Disable  TX/RX request in SSP controller     SSP_DMACmd(SPI_SD, SSP_DMA_Transmit, DISABLE);     SSP_DMACmd(SPI_SD, SSP_DMA_Receive, DISABLE);     DMA_Cmd(DISABLE); }  // str91_dma_transfer_receive

[DGuil]

I am having this issue also. Im using a STR911FAx44. I know this post is old but I would like to see an asnwer. I am in the process of updating legacy firmware and would like to use the DMA. Interrupt does not fire until, what looks like the entire ram space is transferred. I am transferring to the UART in my case.