Fixed USBtoSerial and XPLAINBridge demos discarding data from the PC if the send...

[pub/USBasp.git] / Projects / XPLAINBridge / XPLAINBridge.c

diff --git a/Projects/XPLAINBridge/XPLAINBridge.c b/Projects/XPLAINBridge/XPLAINBridge.c
index 8cd1b2d..d645ebe 100644 (file)
--- a/Projects/XPLAINBridge/XPLAINBridge.c
+++ b/Projects/XPLAINBridge/XPLAINBridge.c
@@ -119,15 +119,21 @@ void UARTBridge_Task(void)
        if (USB_DeviceState != DEVICE_STATE_Configured)
          return;
 
-       /* Read bytes from the USB OUT endpoint into the UART transmit buffer */
-       int16_t ReceivedByte = CDC_Device_ReceiveByte(&VirtualSerial_CDC_Interface);
-       if (!(ReceivedByte < 0) && !(RingBuffer_IsFull(&USBtoUART_Buffer)))
-         RingBuffer_Insert(&USBtoUART_Buffer, ReceivedByte);
+       /* Only try to read in bytes from the CDC interface if the transmit buffer is not full */
+       if (!(RingBuffer_IsFull(&USBtoUART_Buffer)))
+       {
+               int16_t ReceivedByte = CDC_Device_ReceiveByte(&VirtualSerial_CDC_Interface);
 
+               /* Read bytes from the USB OUT endpoint into the UART transmit buffer */
+               if (!(ReceivedByte < 0))
+                 RingBuffer_Insert(&USBtoUART_Buffer, ReceivedByte);
+       }
+       
        /* Check if the UART receive buffer flush timer has expired or buffer is nearly full */
        RingBuff_Count_t BufferCount = RingBuffer_GetCount(&UARTtoUSB_Buffer);
        if ((TIFR0 & (1 << TOV0)) || (BufferCount > 200))
        {
+               /* Clear flush timer expiry flag */
                TIFR0 |= (1 << TOV0);
 
                /* Read bytes from the UART receive buffer into the USB IN endpoint */