[En-Nut-Discussion] Using USART to Rx from PC Keyboard

[Dave Smart]

Hi Harald,

Just to be in the request queue, I'm hoping that your new driver will
support the synchronous mode of the built-in USARTs.

As you may recall, I was having some problems with the sync mode. I haven't
proved the cause, but I have it working now based on the 2.5.2 code base.

What I changed from my earlier post of the code was relatively minor, and I
need to back the change out to verify that it then fails - thus proving the
change.

Surrounding each UartAvrSet<feature> modification, I disabled and then
enabled the USART. Here is one example, and note that I only applied this to
receiver of UART1, since that was the port I was using -

/*
 * \param parm Zero sets async, One sets Sync mode
 *
 * \param dev Indicates the UART device.
 *
 * \return 0 on success, -1 otherwise.
 */
static int UartAvrSetSync(UARTDCB *dcb, u_long parm, u_char devnum)
{
	u_char bits = (parm & 1) << 6;	// Position to 0x40
#ifdef UCSR1C
    if (devnum)
		{
		UCSR1B &= ~0x10;		// disable receiver
		UCSR1C = (UCSR1C & ~0x40) | bits;
		UCSR1B |= 0x10;		// enable receiver
		}
    else
#endif
		UCSR0C = (UCSR0C & ~0x40) | bits;
    return 0;
}


Like I say, I haven't proven that to be the solution, and I didn't find
anything in the manual to support this, but it is now working for me.

kind regards,
Dave Smart