[En-Nut-Discussion] Bug in half duplex mode

[Andrej Taran]

Hi all

Another bug in half duplex mode in file usartavr.c.
At uart speed 115200 and CPU_FREQ = 7,3728 MHz some bytes transmit not 
correct.

The solve this problem.

1. In AvrUsartTxStart delete control of UART_HDX_BIT:

static void AvrUsartTxStart(void)
{
//#ifdef UART_HDX_BIT
//    if (hdx_control) {
//        /* Enable half duplex transmitter. */
//	  UART_HDX_TX(UART_HDX_PORT, UART_HDX_BIT);
//    }
//#endif
     /* Enable transmit interrupts. */
     sbi(UCSRnB, UDRIE);
}


2. And add control of UART_HDX_BIT in AvrUsartTxEmpty:

...
#ifdef UART_HDX_BIT
         if (hdx_control) {
           /* Enable half duplex transmitter. */
           UART_HDX_TX(UART_HDX_PORT, UART_HDX_BIT);
           sbi(UCSRnA, TXC);  /* clear TXC bit, it is very important */
         }
#endif
         /*
          * Start transmission of the next character.
          */
         outb(UDRn, *cp);

...


Regards,
Andrej Taran