How to use the USB ISO IN Endpoint

loginov · ‎2012-06-21

Posted on June 21, 2012 at 09:40

Hello.

I have a probem with the ISO IN Endpoint. Double buffering is not working.

The STM32F103RD is sending right data only from one buffer. Data from another buffer is wrong.

My code:

/* Initialize Endpoint 1 */

SetEPType(ENDP1, EP_ISOCHRONOUS);

SetEPDblBuffAddr(ENDP1, ENDP1_BUF0Addr, ENDP1_BUF1Addr);

ClearDTOG_RX(ENDP1);

ClearDTOG_TX(ENDP1);

ToggleDTOG_RX(ENDP1);

SetEPTxStatus(ENDP1, EP_TX_NAK);

SetEPRxStatus(ENDP1, EP_RX_DIS);

void SOF_Callback(void)

{

if(bDeviceState == CONFIGURED)

{

if (GetENDPOINT(ENDP1) & EP_DTOG_RX)

{

/*write to ENDP1_BUF0Addr buffer*/

UserToPMABufferCopy(USB_Buf, ENDP1_BUF0Addr, USB_Idx);

SetEPDblBuf0Count(ENDP1,EP_DBUF_IN ,USB_Idx);

}

else

{

/*write to ENDP1_BUF1Addr buffer*/

UserToPMABufferCopy(USB_Buf, ENDP1_BUF1Addr, USB_Idx);

SetEPDblBuf1Count(ENDP1,EP_DBUF_IN ,USB_Idx);

}

SetEPTxValid(ENDP1);

}

Is anyone know what is a problem?

tsuneo · ‎2012-06-22

Posted on June 22, 2012 at 21:23

At initialization,

SetEPTxStatus(ENDP1, EP_TX_NAK); <--- SetEPTxStatus(ENDP1, EP_TX_VALID);

NAK is not allowed on isoc endpoint. Just VALID or DISable.

In SOF_Callback(void),

SetEPTxValid(ENDP1); <--- FreeUserBuffer(ENDP1, EP_DBUF_IN);

TX status doesn't change after transmission. It stays in VALID. So, doesn't need to make it VALID.

FreeUserBuffer() toggles DTOG_RX

Tsuneo