TM4C129XNCZAD: Any sample code for UARTCharPutNonBlocking, using interrupt based communication instead of looping to wait and turn off RS485 transmitter?

Hi Mark,

  This is explained in Peripheral Driver Library user's guide in section 34.3. Please refer to it for details. Basically, you use MAP_xyz and let the build process resolve when to use ROM_xyz or xyz. Using ROM_xyz can save you flash spaces because that API is stored in the ROM and the processor run it out of the ROM but not all APIs are supported in ROM. If ROM_xyz is not available then MAP_xyz will resolve to xyz during build time and eventually the API xyz is stored in flash.

I guess I should have copied a little more so you could see where it was coming from.  This is what I see, starting on Line 100:

//*****************************************************************************
//
// Send a string to the UART.
//
//*****************************************************************************
void
UARTSend(const uint8_t *pui8Buffer, uint32_t ui32Count)
{
//
// Loop while there are more characters to send.
//
while(ui32Count--)
{
//
// Write the next character to the UART.
//
MAP_UARTCharPutNonBlocking(UART0_BASE, *pui8Buffer++);
}
}

Starting on Line 87, I see what you posted:

//
// Loop while there are characters in the receive FIFO.
//
while(MAP_UARTCharsAvail(UART0_BASE))
{
//
// Read the next character from the UART and write it back to the UART.
//
MAP_UARTCharPutNonBlocking(UART0_BASE,
UARTCharGetNonBlocking(UART0_BASE));
}

So if I understand the above correctly, as long as there are characters to read, it gets them and then sends them out immediately.

But in my application I have a complete new message to send that is a response to the message received, not an echo of the message received.  The program was previously set up to send the message and keep looping and waiting until it was completely sent before moving on to execute other parts of the program.  I wanted to just start loading the buffer and then come back to it and keep loading, and then keep checking and eventually turn off the RS485 transmitter.  This is what I did, and it seems to be working well:

// In this function we have successfully stopped looping and waiting for characters to be transmitted
if(characters_to_send_HB)
{
for( i = 0 ; i < 300; i++) // Fill FIFO buffer
{
if(must_resend_char_HB)
global_char_HB = character_to_resend_HB;
else
global_char_HB = get_from_output_buffer_HB();

if ( UARTCharPutNonBlocking(UartPort_HB, global_char_HB) == false ) // character did not go in FIFO, must try again
{
character_to_resend_HB = global_char_HB;
must_resend_char_HB = true;
break;
}
else
{
must_resend_char_HB = false;
}

if(out_wrptr_HB == out_rdptr_HB)
{
Host_1_HB_transmission_finished = true;
characters_to_send_HB = false;
break;
}

}
}