FreeRTOS/Demo/PIC18_WizC/serial/isrSerialTx.c

/*
 * FreeRTOS Kernel V10.3.0
 * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 * http://www.FreeRTOS.org
 * http://aws.amazon.com/freertos
 *
 * 1 tab == 4 spaces!
 */

/*
Changes from V3.0.0
	+ ISRcode pulled inline to reduce stack-usage.

	+ Added functionality to only call vTaskSwitchContext() once
	  when handling multiple interruptsources in a single interruptcall.

	+ Filename changed to a .c extension to allow stepping through code
	  using F7.

Changes from V3.0.1
*/

#ifndef _FREERTOS_SERIAL_ISRSERIALTX_C
#define _FREERTOS_SERIAL_ISRSERIALTX_C

#define serINTERRUPT_DISABLED	( 0 )


{
	/*
	 * Was the interrupt the Tx register becoming empty?
	 */
	if( bTXIF && bTXIE)
	{
		/*
		 * Queue to interface between comms API and interrupt routine.
		*/
		extern QueueHandle_t xCharsForTx;

		/*
		 * Because we are not allowed to use local variables here,
		 * PRODL and PRODH are (ab)used as temporary storage. This
		 * is allowed because these SFR's will be restored before
		 * exiting the ISR.
		 */
		extern char				cChar;
		#pragma locate cChar		&PRODL
		extern portBASE_TYPE		pxTaskWoken;
		#pragma locate pxTaskWoken	&PRODH

		if( xQueueReceiveFromISR( xCharsForTx, &cChar, &pxTaskWoken ) == pdTRUE )
		{
			/*
			 * Send the next character queued for Tx.
			 */
			TXREG = cChar;
		}
		else
		{
			/*
			 * Queue empty, nothing to send.
			 */
			bTXIE = serINTERRUPT_DISABLED;
		}

		/*
		 * If we woke another task, ask for a contextswitch
		 */
		if( pxTaskWoken == pdTRUE )
		{
			uxSwitchRequested = pdTRUE;
		}
	}
}

#endif	/* _FREERTOS_SERIAL_ISRSERIALTX_C */