Registered on :
02-07-2009
Messages : 43
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I can't get the USB Double Buffering working for Transmit
I have it working for a single transmit buffer of 1024 bytes
I am using End Point 6 as the Transmit
I setup double buffering by:
// *********************************************
// Initialize Endpoint 6 IN
// Transmit, Kick off the USB data to be sent
// Do a Double buffer of 512 Bytes
// *********************************************
_SetEPAddress(ENDP6, 6);
// setup USB_EP6R
_SetEPType(ENDP6, EP_BULK);
// Set up USB_Counter6, do Tx for Double Buffered
// set Double Buffer register for larger packets
SetEPDoubleBuff(ENDP6); // Make a Double buffer endpoint
SetEPDblBuffAddr(ENDP6, ENDP6_TXADDR1, ENDP6_TXADDR2);
SetEPDblBuffCount(ENDP6, EP_DBUF_IN, 0); // Set Count & BLsize
_ClearDTOG_RX(ENDP6);
_ToggleDTOG_RX(ENDP6);
_ClearDTOG_TX(ENDP6);
// Sets the Endpoint Tx Status as Not valid
_SetEPRxStatus(ENDP6, EP_RX_DIS);
_SetEPTxStatus(ENDP6, EP_TX_DIS);
I setup the Transmit by checking the DTOG flag
Copy my buffer (ucUSBMirrorBuffer) with a count of usUSBMirrorTailIndx
and then make it VALID
It does this once & crashes
// ***********************************
// Check to do Double Buffering
// Ping-Pong between the two Buffers
// ***********************************
Endpoint_DTOG_Status = GetENDPOINT(ENDP6) & EP_DTOG_TX;
if (Endpoint_DTOG_Status)
{
// Transmit to buffer 1
// Reset buffer 1
UserToPMABufferCopy(ucUSBMirrorBuffer, ENDP6_TXADDR2, usUSBMirrorTailIndx);
SetEPDblBuf1Count(ENDP6, EP_DBUF_IN, usUSBMirrorTailIndx);
_SetEPRxStatus(ENDP6, EP_RX_VALID); // Data Valid so USB can now Transmit it
}
else
{
// Reset buffer 0
UserToPMABufferCopy(ucUSBMirrorBuffer, ENDP6_TXADDR1, usUSBMirrorTailIndx);
SetEPDblBuf0Count(ENDP6, EP_DBUF_IN, usUSBMirrorTailIndx);
_SetEPTxStatus(ENDP6, EP_TX_VALID); // Data Valid so USB can now Transmit it
}
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USB Tx Double Buffer not working
Posted 25-09-2008 at 00:07 
Posted 25-09-2008 at 19:12 