2 FreeRTOS V5.4.2 - Copyright (C) 2009 Real Time Engineers Ltd.
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4 This file is part of the FreeRTOS distribution.
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6 FreeRTOS is free software; you can redistribute it and/or modify it under
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7 the terms of the GNU General Public License (version 2) as published by the
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8 Free Software Foundation and modified by the FreeRTOS exception.
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9 **NOTE** The exception to the GPL is included to allow you to distribute a
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10 combined work that includes FreeRTOS without being obliged to provide the
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11 source code for proprietary components outside of the FreeRTOS kernel.
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12 Alternative commercial license and support terms are also available upon
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13 request. See the licensing section of http://www.FreeRTOS.org for full
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16 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
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17 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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18 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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21 You should have received a copy of the GNU General Public License along
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22 with FreeRTOS; if not, write to the Free Software Foundation, Inc., 59
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23 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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26 ***************************************************************************
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28 * Looking for a quick start? Then check out the FreeRTOS eBook! *
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29 * See http://www.FreeRTOS.org/Documentation for details *
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31 ***************************************************************************
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35 Please ensure to read the configuration and relevant port sections of the
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36 online documentation.
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38 http://www.FreeRTOS.org - Documentation, latest information, license and
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41 http://www.SafeRTOS.com - A version that is certified for use in safety
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44 http://www.OpenRTOS.com - Commercial support, development, porting,
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45 licensing and training services.
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49 BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0.
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52 /* Library includes. */
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57 /* Scheduler includes. */
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58 #include "FreeRTOS.h"
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61 /* Demo application includes. */
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64 #define UART0_Rx_Pin ( 0x0001<< 8 )
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65 #define UART0_Tx_Pin ( 0x0001<< 9 )
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67 #define serINVALID_QUEUE ( ( xQueueHandle ) 0 )
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68 #define serNO_BLOCK ( ( portTickType ) 0 )
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70 /* Macros to turn on and off the Tx empty interrupt. */
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71 #define serINTERRUPT_ON() UART0->IER |= UART_TxHalfEmpty
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72 #define serINTERRUPT_OFF() UART0->IER &= ~UART_TxHalfEmpty
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74 /*-----------------------------------------------------------*/
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76 /* Queues used to hold received characters, and characters waiting to be
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78 static xQueueHandle xRxedChars;
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79 static xQueueHandle xCharsForTx;
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81 /*-----------------------------------------------------------*/
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83 /* Interrupt entry point written in the assembler file serialISR.s79. */
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84 extern void vSerialISREntry( void );
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86 /* The interrupt service routine - called from the assembly entry point. */
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87 __arm void vSerialISR( void );
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89 /*-----------------------------------------------------------*/
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92 * See the serial2.h header file.
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94 xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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96 xComPortHandle xReturn;
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98 /* Create the queues used to hold Rx and Tx characters. */
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99 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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100 xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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102 /* If the queues were created correctly then setup the serial port
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104 if( ( xRxedChars != serINVALID_QUEUE ) && ( xCharsForTx != serINVALID_QUEUE ) )
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106 portENTER_CRITICAL();
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108 /* Setup the UART port pins. */
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109 GPIO_Config( GPIO0, UART0_Tx_Pin, GPIO_AF_PP );
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110 GPIO_Config( GPIO0, UART0_Rx_Pin, GPIO_IN_TRI_CMOS );
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112 /* Configure the UART. */
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113 UART_OnOffConfig( UART0, ENABLE );
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114 UART_FifoConfig( UART0, DISABLE );
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115 UART_FifoReset( UART0, UART_RxFIFO );
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116 UART_FifoReset( UART0, UART_TxFIFO );
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117 UART_LoopBackConfig(UART0, DISABLE );
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118 UART_Config( UART0, ulWantedBaud, UART_NO_PARITY, UART_1_StopBits, UARTM_8D );
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119 UART_RxConfig( UART0, ENABLE );
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121 /* Configure the IEC for the UART interrupts. */
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122 EIC_IRQChannelPriorityConfig( UART0_IRQChannel, 1 );
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123 EIC_IRQChannelConfig( UART0_IRQChannel, ENABLE );
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124 EIC_IRQConfig( ENABLE );
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125 UART_ItConfig( UART0, UART_RxBufFull, ENABLE );
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127 portEXIT_CRITICAL();
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131 xReturn = ( xComPortHandle ) 0;
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134 /* This demo file only supports a single port but we have to return
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135 something to comply with the standard demo header file. */
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138 /*-----------------------------------------------------------*/
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140 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
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142 /* The port handle is not required as this driver only supports one port. */
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145 /* Get the next character from the buffer. Return false if no characters
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146 are available, or arrive before xBlockTime expires. */
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147 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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156 /*-----------------------------------------------------------*/
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158 void vSerialPutString( xComPortHandle pxPort, const signed portCHAR * const pcString, unsigned portSHORT usStringLength )
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160 signed portCHAR *pxNext;
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162 /* A couple of parameters that this port does not use. */
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163 ( void ) usStringLength;
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166 /* NOTE: This implementation does not handle the queue being full as no
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167 block time is used! */
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169 /* The port handle is not required as this driver only supports UART0. */
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172 /* Send each character in the string, one at a time. */
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173 pxNext = ( signed portCHAR * ) pcString;
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176 xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
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180 /*-----------------------------------------------------------*/
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182 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
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184 /* Place the character in the queue of characters to be transmitted. */
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185 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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190 /* Turn on the Tx interrupt so the ISR will remove the character from the
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191 queue and send it. This does not need to be in a critical section as
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192 if the interrupt has already removed the character the next interrupt
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193 will simply turn off the Tx interrupt again. */
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198 /*-----------------------------------------------------------*/
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200 void vSerialClose( xComPortHandle xPort )
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202 /* Not supported as not required by the demo application. */
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204 /*-----------------------------------------------------------*/
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206 /* Serial port ISR. This can cause a context switch so is not defined as a
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207 standard ISR using the __irq keyword. Instead a wrapper function is defined
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208 within serialISR.s79 which in turn calls this function. See the port
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209 documentation on the FreeRTOS.org website for more information. */
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210 __arm void vSerialISR( void )
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212 unsigned portSHORT usStatus;
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213 signed portCHAR cChar;
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214 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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216 /* What caused the interrupt? */
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217 usStatus = UART_FlagStatus( UART0 );
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219 if( usStatus & UART_TxHalfEmpty )
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221 /* The interrupt was caused by the THR becoming empty. Are there any
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222 more characters to transmit? */
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223 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
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225 /* A character was retrieved from the queue so can be sent to the
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227 UART0->TxBUFR = cChar;
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231 /* Queue empty, nothing to send so turn off the Tx interrupt. */
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232 serINTERRUPT_OFF();
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236 if( usStatus & UART_RxBufFull )
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238 /* The interrupt was caused by a character being received. Grab the
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239 character from the RHR and place it in the queue of received
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241 cChar = UART0->RxBUFR;
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242 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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245 /* If a task was woken by either a character being received or a character
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246 being transmitted then we may need to switch to another task. */
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247 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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249 /* End the interrupt in the EIC. */
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