finally got TX working without any delay, there is some weird timing involved in what happens when the line state is toggled (host port disconnected) and theres still data waiting to go out, this will hang any while(txCount != 0) calls. similarly, sending data without checking txCount != 0 will hard fault the chip. This is all handled now by usbSendBytes, which returns -1 for unconnected, and 0 for simply 'waiting to send'

1 files changed, 43 insertions, 11 deletions

diff --git a/core/usb/usb_callbacks.c b/core/usb/usb_callbacks.c
index 83b39c7..402e8f5 100644
--- a/core/usb/usb_callbacks.c
+++ b/core/usb/usb_callbacks.c
@@ -31,28 +31,54 @@ USB_Line_Coding line_coding = {
  datatype:    0x08
 };
 
-uint8 vcomBufferTx[VCOM_TX_EPSIZE];
 uint8 vcomBufferRx[VCOM_RX_EPSIZE];
-uint8 countTx = 0;
-uint8 countRx = 0;
+uint8 countTx    = 0;
+uint8 recvBufIn  = 0;
+uint8 recvBufOut = 0;
+uint8 maxNewBytes   = VCOM_RX_EPSIZE;
 
 RESET_STATE reset_state = START;
 
 void vcomDataTxCb(void) {
   /* do whatever after data has been sent to host */
+
+  /* allows usbSendBytes to stop blocking */
+
+
   countTx = 0;
 }
 
+/* we could get arbitrarily complicated here for speed purposes
+   however, the simple scheme here is to implement a receive fifo
+   and always set the maximum to new bytes to the space remaining
+   in the fifo. this number will be reincremented after calls
+   to usbReceiveBytes */
 void vcomDataRxCb(void) {
   /* do whatever after data has been received from host */
- /*  countRx = GetEPRxCount(VCOM_RX_ENDP); */
-/*   PMAToUserBufferCopy(vcomBufferRx,VCOM_RX_ADDR,countRx); */
-/*   SetEPRxValid(VCOM_RX_ENDP); */
 
-/*   countTx = countRx; */
-/*   UserToPMABufferCopy(vcomBufferRx,VCOM_TX_ADDR,countTx); */
-/*   SetEPTxCount(VCOM_TX_ENDP,countTx); */
-/*   SetEPTxValid(VCOM_TX_ENDP); */
+  /* setEPRxCount on the previous cycle should garuntee
+     we havnt received more bytes than we can fit */
+  uint8 newBytes = _GetEPRxCount(VCOM_RX_ENDP);
+  /* assert (newBytes <= maxNewBytes); */
+
+  if (recvBufIn + newBytes < VCOM_RX_EPSIZE) {
+    PMAToUserBufferCopy(&vcomBufferRx[recvBufIn],VCOM_RX_ADDR,newBytes);
+    recvBufIn += newBytes;
+  } else {
+    /* we have to copy the data in two chunks because we roll over
+       the edge of the circular buffer */
+    uint8 tailBytes = VCOM_RX_EPSIZE - recvBufIn;
+    uint8 remaining = newBytes - tailBytes;
+
+    PMAToUserBufferCopy(&vcomBufferRx[recvBufIn],VCOM_RX_ADDR,tailBytes);
+    PMAToUserBufferCopy(&vcomBufferRx[0],        VCOM_RX_ADDR,remaining);
+
+    recvBufIn += (newBytes % VCOM_RX_EPSIZE);
+  }
+  
+  maxNewBytes    -= newBytes;
+  SetEPRxCount(VCOM_RX_ENDP,maxNewBytes);
+  SetEPRxValid(VCOM_RX_ENDP);
 }
 
 void vcomManagementCb(void) {
@@ -115,12 +141,18 @@ void usbReset(void) {
 
   /* setup data endpoint IN (tx)  */
   SetEPType     (VCOM_TX_ENDP, EP_BULK);
-  SetEPRxAddr   (VCOM_TX_ENDP, VCOM_TX_ADDR);
+  SetEPTxAddr   (VCOM_TX_ENDP, VCOM_TX_ADDR);
   SetEPTxStatus (VCOM_TX_ENDP, EP_TX_NAK);
   SetEPRxStatus (VCOM_TX_ENDP, EP_RX_DIS);
 
   bDeviceState = ATTACHED;
   SetDeviceAddress(0);
+
+  /* reset the rx fifo */
+  recvBufIn   = 0;
+  recvBufOut  = 0;
+  maxNewBytes = VCOM_RX_EPSIZE;
+  countTx     = 0;
 }