/*\r
- FreeRTOS V6.1.0 - Copyright (C) 2010 Real Time Engineers Ltd.\r
+ FreeRTOS V6.1.1 - Copyright (C) 2011 Real Time Engineers Ltd.\r
\r
***************************************************************************\r
* *\r
\r
/* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER.\r
*\r
- * This file only supports UART A0 in loopback mode, and has not been tested\r
- * for real UART operation (only loopback mode) so is not guaranteed to have\r
- * a correct baud rate configuration.\r
+ * This is not a proper UART driver. It only supports one port, uses loopback\r
+ * mode, and is used to test interrupts that use the FreeRTOS API as part of\r
+ * a wider test suite. Nor is it intended to show an efficient implementation\r
+ * of a UART interrupt service routine as queues are used to pass individual\r
+ * characters one at a time!\r
*/\r
\r
/* Standard includes. */\r
/* Demo application includes. */\r
#include "serial.h"\r
\r
-/* Constants required to setup the hardware. */\r
-#define serTX_AND_RX ( ( unsigned portCHAR ) 0x03 )\r
-\r
/* Misc. constants. */\r
#define serNO_BLOCK ( ( portTickType ) 0 )\r
\r
}\r
portEXIT_CRITICAL();\r
\r
- /* Unlike other ports, this serial code does not allow for more than one\r
- com port. We therefore don't return a pointer to a port structure and can\r
- instead just return NULL. */\r
+ /* Note the comments at the top of this file about this not being a generic\r
+ UART driver. */\r
return NULL;\r
}\r
/*-----------------------------------------------------------*/\r
{\r
signed portBASE_TYPE xReturn;\r
\r
+ /* Send the next character to the queue of characters waiting transmission,\r
+ then enable the UART Tx interrupt, just in case UART transmission has already\r
+ completed and switched itself off. */\r
xReturn = xQueueSend( xCharsForTx, &cOutChar, xBlockTime );\r
UCA1IE |= UCTXIE;\r
\r
/*-----------------------------------------------------------*/\r
\r
#pragma vector=USCI_A1_VECTOR\r
-static __interrupt void prvUSCI_A0_ISR( void )\r
+static __interrupt void prvUSCI_A1_ISR( void )\r
{\r
-signed portCHAR cChar;\r
-portBASE_TYPE xTaskWoken = pdFALSE;\r
+signed char cChar;\r
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;\r
\r
while( ( UCA1IFG & UCRXIFG ) != 0 )\r
{\r
/* The previous character has been transmitted. See if there are any\r
further characters waiting transmission. */\r
- if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xTaskWoken ) == pdTRUE )\r
+ if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )\r
{\r
/* There was another character queued - transmit it now. */\r
UCA1TXBUF = cChar;\r
}\r
\r
__bic_SR_register_on_exit( SCG1 + SCG0 + OSCOFF + CPUOFF );\r
+ \r
+ /* If writing to a queue caused a task to unblock, and the unblocked task\r
+ has a priority equal to or above the task that this interrupt interrupted,\r
+ then lHigherPriorityTaskWoken will have been set to pdTRUE internally within\r
+ xQueuesendFromISR(), and portEND_SWITCHING_ISR() will ensure that this\r
+ interrupt returns directly to the higher priority unblocked task.\r
+ \r
+ THIS MUST BE THE LAST THING DONE IN THE ISR. */ \r
portYIELD_FROM_ISR( xHigherPriorityTaskWoken );\r
}\r
\r