2 FreeRTOS.org V4.0.2 - Copyright (C) 2003-2006 Richard Barry.
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4 This file is part of the FreeRTOS.org distribution.
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6 FreeRTOS.org is free software; you can redistribute it and/or modify
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7 it under the terms of the GNU General Public License as published by
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8 the Free Software Foundation; either version 2 of the License, or
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9 (at your option) any later version.
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11 FreeRTOS.org is distributed in the hope that it will be useful,
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12 but WITHOUT ANY WARRANTY; without even the implied warranty of
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13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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14 GNU General Public License for more details.
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16 You should have received a copy of the GNU General Public License
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17 along with FreeRTOS.org; if not, write to the Free Software
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18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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20 A special exception to the GPL can be applied should you wish to distribute
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21 a combined work that includes FreeRTOS.org, without being obliged to provide
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22 the source code for any proprietary components. See the licensing section
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23 of http://www.FreeRTOS.org for full details of how and when the exception
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26 ***************************************************************************
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27 See http://www.FreeRTOS.org for documentation, latest information, license
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28 and contact details. Please ensure to read the configuration and relevant
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29 port sections of the online documentation.
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30 ***************************************************************************
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34 BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR USART0.
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36 This file contains all the serial port components that can be compiled to
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37 either ARM or THUMB mode. Components that must be compiled to ARM mode are
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38 contained in serialISR.c.
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41 /* Standard includes. */
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44 /* Scheduler includes. */
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45 #include "FreeRTOS.h"
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49 /* Demo application includes. */
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51 #include "AT91R40008.h"
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56 /*-----------------------------------------------------------*/
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58 /* Constants to setup and access the UART. */
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59 #define portUSART0_AIC_CHANNEL ( ( unsigned portLONG ) 2 )
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61 #define serINVALID_QUEUE ( ( xQueueHandle ) 0 )
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62 #define serHANDLE ( ( xComPortHandle ) 1 )
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63 #define serNO_BLOCK ( ( portTickType ) 0 )
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65 /*-----------------------------------------------------------*/
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67 /* Queues used to hold received characters, and characters waiting to be
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69 static xQueueHandle xRxedChars;
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70 static xQueueHandle xCharsForTx;
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72 /*-----------------------------------------------------------*/
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75 * The queues are created in serialISR.c as they are used from the ISR.
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76 * Obtain references to the queues and THRE Empty flag.
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78 extern void vSerialISRCreateQueues( unsigned portBASE_TYPE uxQueueLength, xQueueHandle *pxRxedChars, xQueueHandle *pxCharsForTx );
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80 /*-----------------------------------------------------------*/
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82 xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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84 unsigned portLONG ulSpeed;
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85 unsigned portLONG ulCD;
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86 xComPortHandle xReturn = serHANDLE;
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87 extern void ( vUART_ISR )( void );
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89 /* The queues are used in the serial ISR routine, so are created from
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90 serialISR.c (which is always compiled to ARM mode. */
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91 vSerialISRCreateQueues( uxQueueLength, &xRxedChars, &xCharsForTx );
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94 ( xRxedChars != serINVALID_QUEUE ) &&
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95 ( xCharsForTx != serINVALID_QUEUE ) &&
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96 ( ulWantedBaud != ( unsigned portLONG ) 0 )
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99 portENTER_CRITICAL();
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101 /* Enable clock to USART0... */
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102 AT91C_BASE_PS->PS_PCER = AT91C_PS_US0;
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104 /* Disable all USART0 interrupt sources to begin... */
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105 AT91C_BASE_US0->US_IDR = 0xFFFFFFFF;
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107 /* Reset various status bits (just in case)... */
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108 AT91C_BASE_US0->US_CR = US_RSTSTA;
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110 AT91C_BASE_PIO->PIO_PDR = TXD0 | RXD0; /* Enable RXD and TXD pins */
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111 AT91C_BASE_US0->US_CR = US_RSTRX | US_RSTTX | US_RXDIS | US_TXDIS;
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113 /* Clear Transmit and Receive Counters */
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114 AT91C_BASE_US0->US_RCR = 0;
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115 AT91C_BASE_US0->US_TCR = 0;
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117 /* Input clock to baud rate generator is MCK */
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118 ulSpeed = configCPU_CLOCK_HZ * 10;
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119 ulSpeed = ulSpeed / 16;
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120 ulSpeed = ulSpeed / ulWantedBaud;
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122 /* compute the error */
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123 ulCD = ulSpeed / 10;
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124 if ((ulSpeed - (ulCD * 10)) >= 5)
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127 /* Define the baud rate divisor register */
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128 AT91C_BASE_US0->US_BRGR = ulCD;
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130 /* Define the USART mode */
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131 AT91C_BASE_US0->US_MR = US_CLKS_MCK | US_CHRL_8 | US_PAR_NO | US_NBSTOP_1 | US_CHMODE_NORMAL;
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133 /* Write the Timeguard Register */
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134 AT91C_BASE_US0->US_TTGR = 0;
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136 /* Setup the interrupt for USART0.
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138 Store interrupt handler function address in USART0 vector register... */
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139 AT91C_BASE_AIC->AIC_SVR[ portUSART0_AIC_CHANNEL ] = (unsigned long)vUART_ISR;
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141 /* USART0 interrupt level-sensitive, priority 1... */
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142 AT91C_BASE_AIC->AIC_SMR[ portUSART0_AIC_CHANNEL ] = AIC_SRCTYPE_INT_LEVEL_SENSITIVE | 1;
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144 /* Clear some pending USART0 interrupts (just in case)... */
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145 AT91C_BASE_US0->US_CR = US_RSTSTA;
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147 /* Enable USART0 interrupt sources (but not Tx for now)... */
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148 AT91C_BASE_US0->US_IER = US_RXRDY;
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150 /* Enable USART0 interrupts in the AIC... */
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151 AT91C_BASE_AIC->AIC_IECR = ( 1 << portUSART0_AIC_CHANNEL );
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153 /* Enable receiver and transmitter... */
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154 AT91C_BASE_US0->US_CR = US_RXEN | US_TXEN;
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156 portEXIT_CRITICAL();
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160 xReturn = ( xComPortHandle ) 0;
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165 /*-----------------------------------------------------------*/
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167 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
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169 /* The port handle is not required as this driver only supports UART0. */
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172 /* Get the next character from the buffer. Return false if no characters
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173 are available, or arrive before xBlockTime expires. */
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174 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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183 /*-----------------------------------------------------------*/
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185 void vSerialPutString( xComPortHandle pxPort, const signed portCHAR * const pcString, unsigned portSHORT usStringLength )
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187 signed portCHAR *pxNext;
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189 /* NOTE: This implementation does not handle the queue being full as no
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190 block time is used! */
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192 /* The port handle is not required as this driver only supports UART0. */
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195 /* Send each character in the string, one at a time. */
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196 pxNext = ( signed portCHAR * ) pcString;
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199 xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
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203 /*-----------------------------------------------------------*/
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205 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
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207 /* Place the character in the queue of characters to be transmitted. */
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208 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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213 /* Turn on the Tx interrupt so the ISR will remove the character from the
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214 queue and send it. This does not need to be in a critical section as
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215 if the interrupt has already removed the character the next interrupt
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216 will simply turn off the Tx interrupt again. */
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217 AT91C_BASE_US0->US_IER = US_TXRDY;
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221 /*-----------------------------------------------------------*/
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223 void vSerialClose( xComPortHandle xPort )
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225 /* Not supported as not required by the demo application. */
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227 /*-----------------------------------------------------------*/
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