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 USART0.
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51 This file contains all the serial port components that can be compiled to
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52 either ARM or THUMB mode. Components that must be compiled to ARM mode are
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53 contained in serialISR.c.
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56 /* Standard includes. */
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59 /* Scheduler includes. */
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60 #include "FreeRTOS.h"
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64 /* Demo application includes. */
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66 #include "AT91R40008.h"
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71 /*-----------------------------------------------------------*/
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73 /* Constants to setup and access the UART. */
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74 #define portUSART0_AIC_CHANNEL ( ( unsigned portLONG ) 2 )
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76 #define serINVALID_QUEUE ( ( xQueueHandle ) 0 )
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77 #define serHANDLE ( ( xComPortHandle ) 1 )
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78 #define serNO_BLOCK ( ( portTickType ) 0 )
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80 /*-----------------------------------------------------------*/
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82 /* Queues used to hold received characters, and characters waiting to be
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84 static xQueueHandle xRxedChars;
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85 static xQueueHandle xCharsForTx;
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87 /*-----------------------------------------------------------*/
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90 * The queues are created in serialISR.c as they are used from the ISR.
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91 * Obtain references to the queues and THRE Empty flag.
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93 extern void vSerialISRCreateQueues( unsigned portBASE_TYPE uxQueueLength, xQueueHandle *pxRxedChars, xQueueHandle *pxCharsForTx );
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95 /*-----------------------------------------------------------*/
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97 xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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99 unsigned portLONG ulSpeed;
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100 unsigned portLONG ulCD;
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101 xComPortHandle xReturn = serHANDLE;
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102 extern void ( vUART_ISR_Wrapper )( void );
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104 /* The queues are used in the serial ISR routine, so are created from
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105 serialISR.c (which is always compiled to ARM mode. */
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106 vSerialISRCreateQueues( uxQueueLength, &xRxedChars, &xCharsForTx );
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109 ( xRxedChars != serINVALID_QUEUE ) &&
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110 ( xCharsForTx != serINVALID_QUEUE ) &&
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111 ( ulWantedBaud != ( unsigned portLONG ) 0 )
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114 portENTER_CRITICAL();
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116 /* Enable clock to USART0... */
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117 AT91C_BASE_PS->PS_PCER = AT91C_PS_US0;
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119 /* Disable all USART0 interrupt sources to begin... */
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120 AT91C_BASE_US0->US_IDR = 0xFFFFFFFF;
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122 /* Reset various status bits (just in case)... */
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123 AT91C_BASE_US0->US_CR = US_RSTSTA;
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125 AT91C_BASE_PIO->PIO_PDR = TXD0 | RXD0; /* Enable RXD and TXD pins */
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126 AT91C_BASE_US0->US_CR = US_RSTRX | US_RSTTX | US_RXDIS | US_TXDIS;
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128 /* Clear Transmit and Receive Counters */
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129 AT91C_BASE_US0->US_RCR = 0;
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130 AT91C_BASE_US0->US_TCR = 0;
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132 /* Input clock to baud rate generator is MCK */
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133 ulSpeed = configCPU_CLOCK_HZ * 10;
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134 ulSpeed = ulSpeed / 16;
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135 ulSpeed = ulSpeed / ulWantedBaud;
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137 /* compute the error */
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138 ulCD = ulSpeed / 10;
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139 if ((ulSpeed - (ulCD * 10)) >= 5)
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142 /* Define the baud rate divisor register */
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143 AT91C_BASE_US0->US_BRGR = ulCD;
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145 /* Define the USART mode */
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146 AT91C_BASE_US0->US_MR = US_CLKS_MCK | US_CHRL_8 | US_PAR_NO | US_NBSTOP_1 | US_CHMODE_NORMAL;
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148 /* Write the Timeguard Register */
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149 AT91C_BASE_US0->US_TTGR = 0;
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151 /* Setup the interrupt for USART0.
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153 Store interrupt handler function address in USART0 vector register... */
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154 AT91C_BASE_AIC->AIC_SVR[ portUSART0_AIC_CHANNEL ] = (unsigned long)vUART_ISR_Wrapper;
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156 /* USART0 interrupt level-sensitive, priority 1... */
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157 AT91C_BASE_AIC->AIC_SMR[ portUSART0_AIC_CHANNEL ] = AIC_SRCTYPE_INT_LEVEL_SENSITIVE | 1;
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159 /* Clear some pending USART0 interrupts (just in case)... */
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160 AT91C_BASE_US0->US_CR = US_RSTSTA;
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162 /* Enable USART0 interrupt sources (but not Tx for now)... */
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163 AT91C_BASE_US0->US_IER = US_RXRDY;
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165 /* Enable USART0 interrupts in the AIC... */
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166 AT91C_BASE_AIC->AIC_IECR = ( 1 << portUSART0_AIC_CHANNEL );
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168 /* Enable receiver and transmitter... */
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169 AT91C_BASE_US0->US_CR = US_RXEN | US_TXEN;
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171 portEXIT_CRITICAL();
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175 xReturn = ( xComPortHandle ) 0;
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180 /*-----------------------------------------------------------*/
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182 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
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184 /* The port handle is not required as this driver only supports UART0. */
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187 /* Get the next character from the buffer. Return false if no characters
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188 are available, or arrive before xBlockTime expires. */
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189 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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198 /*-----------------------------------------------------------*/
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200 void vSerialPutString( xComPortHandle pxPort, const signed portCHAR * const pcString, unsigned portSHORT usStringLength )
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202 signed portCHAR *pxNext;
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204 /* NOTE: This implementation does not handle the queue being full as no
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205 block time is used! */
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207 /* The port handle is not required as this driver only supports UART0. */
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209 ( void ) usStringLength;
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211 /* Send each character in the string, one at a time. */
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212 pxNext = ( signed portCHAR * ) pcString;
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215 xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
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219 /*-----------------------------------------------------------*/
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221 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
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225 /* Place the character in the queue of characters to be transmitted. */
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226 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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231 /* Turn on the Tx interrupt so the ISR will remove the character from the
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232 queue and send it. This does not need to be in a critical section as
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233 if the interrupt has already removed the character the next interrupt
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234 will simply turn off the Tx interrupt again. */
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235 AT91C_BASE_US0->US_IER = US_TXRDY;
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239 /*-----------------------------------------------------------*/
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241 void vSerialClose( xComPortHandle xPort )
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243 /* Not supported as not required by the demo application. */
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246 /*-----------------------------------------------------------*/
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