2 FreeRTOS V7.0.2 - Copyright (C) 2011 Real Time Engineers Ltd.
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5 ***************************************************************************
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7 * FreeRTOS tutorial books are available in pdf and paperback. *
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8 * Complete, revised, and edited pdf reference manuals are also *
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11 * Purchasing FreeRTOS documentation will not only help you, by *
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12 * ensuring you get running as quickly as possible and with an *
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13 * in-depth knowledge of how to use FreeRTOS, it will also help *
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14 * the FreeRTOS project to continue with its mission of providing *
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15 * professional grade, cross platform, de facto standard solutions *
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16 * for microcontrollers - completely free of charge! *
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18 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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20 * Thank you for using FreeRTOS, and thank you for your support! *
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22 ***************************************************************************
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25 This file is part of the FreeRTOS distribution.
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27 FreeRTOS is free software; you can redistribute it and/or modify it under
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28 the terms of the GNU General Public License (version 2) as published by the
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29 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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30 >>>NOTE<<< The modification to the GPL is included to allow you to
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31 distribute a combined work that includes FreeRTOS without being obliged to
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32 provide the source code for proprietary components outside of the FreeRTOS
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33 kernel. FreeRTOS is distributed in the hope that it will be useful, but
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34 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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35 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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36 more details. You should have received a copy of the GNU General Public
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37 License and the FreeRTOS license exception along with FreeRTOS; if not it
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38 can be viewed here: http://www.freertos.org/a00114.html and also obtained
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39 by writing to Richard Barry, contact details for whom are available on the
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44 http://www.FreeRTOS.org - Documentation, latest information, license and
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47 http://www.SafeRTOS.com - A version that is certified for use in safety
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50 http://www.OpenRTOS.com - Commercial support, development, porting,
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51 licensing and training services.
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55 BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0.
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57 ***Note*** This example uses queues to send each character into an interrupt
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58 service routine and out of an interrupt service routine individually. This
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59 is done to demonstrate queues being used in an interrupt, and to deliberately
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60 load the system to test the FreeRTOS port. It is *NOT* meant to be an
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61 example of an efficient implementation. An efficient implementation should
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62 use FIFOs or DMA if available, and only use FreeRTOS API functions when
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63 enough has been received to warrant a task being unblocked to process the
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67 /* Scheduler includes. */
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68 #include "FreeRTOS.h"
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71 #include "comtest2.h"
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73 /* Library includes. */
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76 /* Demo application includes. */
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78 /*-----------------------------------------------------------*/
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80 /* Register bit definitions. */
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81 #define serRX_INT_ENABLE 0x10
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82 #define serTX_INT_ENABLE 0x08
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83 #define serRX_ENABLE 0x02
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84 #define serTX_ENABLE 0x01
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85 #define serORE_ERROR_BIT 0x08
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86 #define serFRE_ERROR_BIT 0x10
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87 #define serPE_ERROR_BIT 0x20
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88 #define serRX_INT 0x04
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89 #define serTX_INT 0x02
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92 #define serINVALID_QUEUE ( ( xQueueHandle ) 0 )
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93 #define serNO_BLOCK ( ( portTickType ) 0 )
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95 /*-----------------------------------------------------------*/
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97 /* The queue used to hold received characters. */
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98 static xQueueHandle xRxedChars;
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99 static xQueueHandle xCharsForTx;
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101 /*-----------------------------------------------------------*/
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104 * See the serial2.h header file.
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106 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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108 /* Create the queues used to hold Rx/Tx characters. */
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109 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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110 xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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112 /* If the queues were created correctly then setup the serial port
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114 if( ( xRxedChars != serINVALID_QUEUE ) && ( xCharsForTx != serINVALID_QUEUE ) )
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116 /* Ensure interrupts don't fire during the init process. Interrupts
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117 will be enabled automatically when the first task start running. */
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118 portDISABLE_INTERRUPTS();
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120 /* Configure P21 and P22 for use by the UART. */
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121 FM3_GPIO->PFR2 |= ( 1 << 0x01 ) | ( 1 << 0x02 );
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123 /* SIN0_0 and SOT0_0. */
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124 FM3_GPIO->EPFR07 |= ( 1 << 6 );
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127 FM3_MFS0_UART->SCR = 0x80;
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129 /* Enable output in mode 0. */
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130 FM3_MFS0_UART->SMR = 0x01;
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132 /* Clear all errors that may already be present. */
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133 FM3_MFS0_UART->SSR = 0x00;
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134 FM3_MFS0_UART->ESCR = 0x00;
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136 FM3_MFS0_UART->BGR = ( configCPU_CLOCK_HZ / 2UL ) / ( ulWantedBaud - 1UL );
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138 /* Enable Rx, Tx, and the Rx interrupt. */
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139 FM3_MFS0_UART->SCR |= ( serRX_ENABLE | serTX_ENABLE | serRX_INT_ENABLE );
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141 /* Configure the NVIC for UART interrupts. */
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142 NVIC_ClearPendingIRQ( MFS0RX_IRQn );
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143 NVIC_EnableIRQ( MFS0RX_IRQn );
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145 /* The priority *MUST* be at or below
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146 configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY as FreeRTOS API functions
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147 are called in the interrupt handler. */
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148 NVIC_SetPriority( MFS0RX_IRQn, configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY );
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150 /* Do the same for the Tx interrupts. */
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151 NVIC_ClearPendingIRQ( MFS0TX_IRQn );
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152 NVIC_EnableIRQ( MFS0TX_IRQn );
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154 /* The priority *MUST* be at or below
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155 configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY as FreeRTOS API functions
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156 are called in the interrupt handler. */
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157 NVIC_SetPriority( MFS0TX_IRQn, configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY );
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160 /* This demo file only supports a single port but we have to return
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161 something to comply with the standard demo header file. */
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162 return ( xComPortHandle ) 0;
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164 /*-----------------------------------------------------------*/
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166 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
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168 /* The port handle is not required as this driver only supports one port. */
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171 /* Get the next character from the buffer. Return false if no characters
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172 are available, or arrive before xBlockTime expires. */
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173 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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182 /*-----------------------------------------------------------*/
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184 void vSerialPutString( xComPortHandle pxPort, const signed char * const pcString, unsigned short usStringLength )
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186 signed char *pxNext;
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188 /* A couple of parameters that this port does not use. */
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189 ( void ) usStringLength;
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192 /* NOTE: This implementation does not handle the queue being full as no
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193 block time is used! */
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195 /* The port handle is not required as this driver only supports one UART. */
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198 /* Send each character in the string, one at a time. */
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199 pxNext = ( signed char * ) pcString;
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202 xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
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206 /*-----------------------------------------------------------*/
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208 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
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210 signed portBASE_TYPE xReturn;
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212 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) == pdPASS )
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216 /* Enable the UART Tx interrupt. */
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217 FM3_MFS0_UART->SCR |= serTX_INT_ENABLE;
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226 /*-----------------------------------------------------------*/
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228 void vSerialClose( xComPortHandle xPort )
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230 /* Not supported as not required by the demo application. */
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232 /*-----------------------------------------------------------*/
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234 void MFS0RX_IRQHandler( void )
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236 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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239 if( ( FM3_MFS0_UART->SSR & ( serORE_ERROR_BIT | serFRE_ERROR_BIT | serPE_ERROR_BIT ) ) != 0 )
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241 /* A PE, ORE or FRE error occurred. Clear it. */
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242 FM3_MFS0_UART->SSR |= ( 1 << 7 );
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243 cChar = FM3_MFS0_UART->RDR;
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245 else if( FM3_MFS0_UART->SSR & serRX_INT )
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247 /* A character has been received on the USART, send it to the Rx
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249 cChar = FM3_MFS0_UART->RDR;
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250 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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253 /* If sending or receiving from a queue has caused a task to unblock, and
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254 the unblocked task has a priority equal to or higher than the currently
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255 running task (the task this ISR interrupted), then xHigherPriorityTaskWoken
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256 will have automatically been set to pdTRUE within the queue send or receive
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257 function. portEND_SWITCHING_ISR() will then ensure that this ISR returns
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258 directly to the higher priority unblocked task. */
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259 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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261 /*-----------------------------------------------------------*/
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263 void MFS0TX_IRQHandler( void )
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265 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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268 if( FM3_MFS0_UART->SSR & serTX_INT )
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270 /* The interrupt was caused by the TX register becoming empty. Are
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271 there any more characters to transmit? */
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272 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
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274 /* A character was retrieved from the queue so can be sent to the
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276 FM3_MFS0_UART->TDR = cChar;
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280 /* Disable the Tx interrupt. */
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281 FM3_MFS0_UART->SCR &= ~serTX_INT_ENABLE;
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285 /* If sending or receiving from a queue has caused a task to unblock, and
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286 the unblocked task has a priority equal to or higher than the currently
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287 running task (the task this ISR interrupted), then xHigherPriorityTaskWoken
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288 will have automatically been set to pdTRUE within the queue send or receive
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289 function. portEND_SWITCHING_ISR() will then ensure that this ISR returns
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290 directly to the higher priority unblocked task. */
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291 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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