2 FreeRTOS V7.3.0 - Copyright (C) 2012 Real Time Engineers Ltd.
\r
4 FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME. PLEASE VISIT
\r
5 http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
\r
7 ***************************************************************************
\r
9 * FreeRTOS tutorial books are available in pdf and paperback. *
\r
10 * Complete, revised, and edited pdf reference manuals are also *
\r
13 * Purchasing FreeRTOS documentation will not only help you, by *
\r
14 * ensuring you get running as quickly as possible and with an *
\r
15 * in-depth knowledge of how to use FreeRTOS, it will also help *
\r
16 * the FreeRTOS project to continue with its mission of providing *
\r
17 * professional grade, cross platform, de facto standard solutions *
\r
18 * for microcontrollers - completely free of charge! *
\r
20 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
\r
22 * Thank you for using FreeRTOS, and thank you for your support! *
\r
24 ***************************************************************************
\r
27 This file is part of the FreeRTOS distribution.
\r
29 FreeRTOS is free software; you can redistribute it and/or modify it under
\r
30 the terms of the GNU General Public License (version 2) as published by the
\r
31 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
\r
32 >>>NOTE<<< The modification to the GPL is included to allow you to
\r
33 distribute a combined work that includes FreeRTOS without being obliged to
\r
34 provide the source code for proprietary components outside of the FreeRTOS
\r
35 kernel. FreeRTOS is distributed in the hope that it will be useful, but
\r
36 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
\r
37 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
\r
38 more details. You should have received a copy of the GNU General Public
\r
39 License and the FreeRTOS license exception along with FreeRTOS; if not it
\r
40 can be viewed here: http://www.freertos.org/a00114.html and also obtained
\r
41 by writing to Richard Barry, contact details for whom are available on the
\r
46 ***************************************************************************
\r
48 * Having a problem? Start by reading the FAQ "My application does *
\r
49 * not run, what could be wrong?" *
\r
51 * http://www.FreeRTOS.org/FAQHelp.html *
\r
53 ***************************************************************************
\r
56 http://www.FreeRTOS.org - Documentation, training, latest versions, license
\r
57 and contact details.
\r
59 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
\r
60 including FreeRTOS+Trace - an indispensable productivity tool.
\r
62 Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell
\r
63 the code with commercial support, indemnification, and middleware, under
\r
64 the OpenRTOS brand: http://www.OpenRTOS.com. High Integrity Systems also
\r
65 provide a safety engineered and independently SIL3 certified version under
\r
66 the SafeRTOS brand: http://www.SafeRTOS.com.
\r
70 /* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER.
\r
72 * This is not a proper UART driver. It only supports one port, uses loopback
\r
73 * mode, and is used to test interrupts that use the FreeRTOS API as part of
\r
74 * a wider test suite. Nor is it intended to show an efficient implementation
\r
75 * of a UART interrupt service routine as queues are used to pass individual
\r
76 * characters one at a time!
\r
79 /* Standard includes. */
\r
82 /* Scheduler includes. */
\r
83 #include "FreeRTOS.h"
\r
87 /* Demo application includes. */
\r
90 /* Misc. constants. */
\r
91 #define serNO_BLOCK ( ( portTickType ) 0 )
\r
93 /* The queue used to hold received characters. */
\r
94 static xQueueHandle xRxedChars;
\r
96 /* The queue used to hold characters waiting transmission. */
\r
97 static xQueueHandle xCharsForTx;
\r
99 /*-----------------------------------------------------------*/
\r
101 xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
\r
103 unsigned portLONG ulBaudRateCount;
\r
105 /* Initialise the hardware. */
\r
107 /* Generate the baud rate constants for the wanted baud rate. */
\r
108 ulBaudRateCount = configCPU_CLOCK_HZ / ulWantedBaud;
\r
110 portENTER_CRITICAL();
\r
112 /* Create the queues used by the com test task. */
\r
113 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
\r
114 xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
\r
117 UCA1CTL1 |= UCSWRST;
\r
120 UCA1CTL1 = UCSSEL0 | UCSSEL1;
\r
122 /* Setup baud rate low byte. */
\r
123 UCA1BR0 = ( unsigned portCHAR ) ( ulBaudRateCount & ( unsigned portLONG ) 0xff );
\r
125 /* Setup baud rate high byte. */
\r
126 ulBaudRateCount >>= 8UL;
\r
127 UCA1BR1 = ( unsigned portCHAR ) ( ulBaudRateCount & ( unsigned portLONG ) 0xff );
\r
129 /* UCLISTEN sets loopback mode! */
\r
130 UCA1STAT = UCLISTEN;
\r
132 /* Enable interrupts. */
\r
135 /* Take out of reset. */
\r
136 UCA1CTL1 &= ~UCSWRST;
\r
138 portEXIT_CRITICAL();
\r
140 /* Note the comments at the top of this file about this not being a generic
\r
144 /*-----------------------------------------------------------*/
\r
146 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
\r
148 /* Get the next character from the buffer. Return false if no characters
\r
149 are available, or arrive before xBlockTime expires. */
\r
150 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
\r
159 /*-----------------------------------------------------------*/
\r
161 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
\r
163 signed portBASE_TYPE xReturn;
\r
165 /* Send the next character to the queue of characters waiting transmission,
\r
166 then enable the UART Tx interrupt, just in case UART transmission has already
\r
167 completed and switched itself off. */
\r
168 xReturn = xQueueSend( xCharsForTx, &cOutChar, xBlockTime );
\r
173 /*-----------------------------------------------------------*/
\r
175 /* The implementation of this interrupt is provided to demonstrate the use
\r
176 of queues from inside an interrupt service routine. It is *not* intended to
\r
177 be an efficient interrupt implementation. A real application should make use
\r
178 of the DMA. Or, as a minimum, transmission and reception could use a simple
\r
179 RAM ring buffer, and synchronise with a task using a semaphore when a complete
\r
180 message has been received or transmitted. */
\r
181 #pragma vector=USCI_A1_VECTOR
\r
182 static __interrupt void prvUSCI_A1_ISR( void )
\r
185 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
\r
187 while( ( UCA1IFG & UCRXIFG ) != 0 )
\r
189 /* Get the character from the UART and post it on the queue of Rxed
\r
192 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
\r
195 /* If there is a Tx interrupt pending and the tx interrupts are enabled. */
\r
196 if( ( UCA1IFG & UCTXIFG ) != 0 )
\r
198 /* The previous character has been transmitted. See if there are any
\r
199 further characters waiting transmission. */
\r
200 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
\r
202 /* There was another character queued - transmit it now. */
\r
207 /* There were no other characters to transmit - disable the Tx
\r
213 __bic_SR_register_on_exit( SCG1 + SCG0 + OSCOFF + CPUOFF );
\r
215 /* If writing to a queue caused a task to unblock, and the unblocked task
\r
216 has a priority equal to or above the task that this interrupt interrupted,
\r
217 then lHigherPriorityTaskWoken will have been set to pdTRUE internally within
\r
218 xQueuesendFromISR(), and portEND_SWITCHING_ISR() will ensure that this
\r
219 interrupt returns directly to the higher priority unblocked task.
\r
221 THIS MUST BE THE LAST THING DONE IN THE ISR. */
\r
222 portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
\r