USB BULK & DMA

[stefano239955_stm1_stmicro]

Posted on April 26, 2007 at 13:32

USB BULK & DMA

#usb-dma-str9

[kelly23]

Posted on May 17, 2011 at 09:42

Hi Steve,

Have you found a resolution to this problem?  I am also seeking example source code and/or documentation that defines how to enable USB transfers via DMA.

-Kelly

[stefano239955_stm1_stmicro]

Posted on May 17, 2011 at 09:42

Hello,

I need to send to the pc about 64Kbyte of data using a bulk transfer (EP1).

I'd like to use the DMA to do that.

I wrote the following piece of code but I have a doubt:

Have I to trigger the dma event every 64byte or the dma engine is

in charge to manage the transfer of the EP buffer?

Do you have any example?

----- code -----------

DMA_InitTypeDef DMA_init;

DMA_StructInit(&DMA_init);

DMA_init.DMA_Channel_LLstItm=(u32)(USBDMA_Link[2]);

DMA_init.DMA_Channel_DesAdd=(u32)(PMAAddr+(u32)((GetEPDblBuf0Addr(ENDP1)))); /* Destination address Endpoint 1 Buffer 0*/

DMA_init.DMA_Channel_SrcAdd=(u32)(&AD_buffer); /* Source address */

DMA_init.DMA_Channel_SrcWidth= DMA_SrcWidth_Word; /* The source bus width is a word (32bits)*/

DMA_init.DMA_Channel_DesWidth= DMA_DesWidth_Word; /* The Destination bus width is a word (32bits)*/

DMA_init.DMA_Channel_FlowCntrl=DMA_FlowCntrl_Perip2; /* USB is The flow controller*/

DMA_init.DMA_Channel_Des= DMA_SRC_USB_TX;

DMA_init.DMA_Channel_TrsfSize = 0; /* Transfer size*/

/* Configure the DMA channel0 */

DMA_Init(DMA_Channel1, &DMA_init); /* update the DMA channel1 registers with the LLI structure*/

DMALinkedModeTxEnable();

DMASynchEnable();

DMALinkedModeTxConfig(ENDP1);

SetDMALLITxLength(0x4);

DMA_ChannelCmd (DMA_Channel1, ENABLE); /*Enable the DMA channel*/

DMA_ChannelDESIncConfig (DMA_Channel1, ENABLE);

DMA_ChannelSRCIncConfig (DMA_Channel1, ENABLE);

DMA_ITMaskConfig(DMA_Channel1, DMA_ITMask_ITC, ENABLE);

// src

USBDMA_Link[0] = (u32)(&AD_buffer[0x0000]);

USBDMA_Link[4] = (u32)(&AD_buffer[0x0800]);

USBDMA_Link[9] = (u32)(&AD_buffer[0x1000]);

USBDMA_Link[12] = (u32)(&AD_buffer[0x1800]);

//des

USBDMA_Link[1] = (u32)(PMAAddr+(u32)((GetEPDblBuf1Addr(ENDP1))));

USBDMA_Link[5] = (u32)(PMAAddr+(u32)((GetEPDblBuf1Addr(ENDP1))));

USBDMA_Link[10] = (u32)(PMAAddr+(u32)((GetEPDblBuf1Addr(ENDP1))));

USBDMA_Link[13] = (u32)(PMAAddr+(u32)((GetEPDblBuf1Addr(ENDP1))));

USBDMA_Link[2] = (u32)(&USBDMA_Link[4]);

USBDMA_Link[6] = (u32)(&USBDMA_Link[8]);

USBDMA_Link[10] = (u32)(&USBDMA_Link[12]);