2 FreeRTOS.org V5.3.0 - Copyright (C) 2003-2009 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 it
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7 under the terms of the GNU General Public License (version 2) as published
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8 by the 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.org without being obliged to provide
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11 the source code for any proprietary components. Alternative commercial
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12 license and support terms are also available upon request. See the
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13 licensing section of http://www.FreeRTOS.org for full details.
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15 FreeRTOS.org is distributed in the hope that it will be useful, but WITHOUT
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16 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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17 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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20 You should have received a copy of the GNU General Public License along
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21 with FreeRTOS.org; if not, write to the Free Software Foundation, Inc., 59
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22 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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25 ***************************************************************************
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27 * Get the FreeRTOS eBook! See http://www.FreeRTOS.org/Documentation *
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29 * This is a concise, step by step, 'hands on' guide that describes both *
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30 * general multitasking concepts and FreeRTOS specifics. It presents and *
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31 * explains numerous examples that are written using the FreeRTOS API. *
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32 * Full source code for all the examples is provided in an accompanying *
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35 ***************************************************************************
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39 Please ensure to read the configuration and relevant port sections of the
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40 online documentation.
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42 http://www.FreeRTOS.org - Documentation, latest information, license and
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45 http://www.SafeRTOS.com - A version that is certified for use in safety
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48 http://www.OpenRTOS.com - Commercial support, development, porting,
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49 licensing and training services.
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52 /*-----------------------------------------------------------
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53 * Implementation of functions defined in portable.h for the ST STR75x ARM7
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55 *----------------------------------------------------------*/
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57 /* Library includes. */
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59 #include "75x_eic.h"
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61 /* Scheduler includes. */
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62 #include "FreeRTOS.h"
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65 /* Constants required to setup the initial stack. */
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66 #define portINITIAL_SPSR ( ( portSTACK_TYPE ) 0x1f ) /* System mode, ARM mode, interrupts enabled. */
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67 #define portTHUMB_MODE_BIT ( ( portSTACK_TYPE ) 0x20 )
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68 #define portINSTRUCTION_SIZE ( ( portSTACK_TYPE ) 4 )
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70 /* Constants required to handle critical sections. */
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71 #define portNO_CRITICAL_NESTING ( ( unsigned portLONG ) 0 )
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73 /* Prescale used on the timer clock when calculating the tick period. */
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74 #define portPRESCALE 20
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77 /*-----------------------------------------------------------*/
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79 /* Setup the TB to generate the tick interrupts. */
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80 static void prvSetupTimerInterrupt( void );
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82 /*-----------------------------------------------------------*/
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85 * Initialise the stack of a task to look exactly as if a call to
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86 * portSAVE_CONTEXT had been called.
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88 * See header file for description.
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90 portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
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92 portSTACK_TYPE *pxOriginalTOS;
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94 pxOriginalTOS = pxTopOfStack;
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96 /* Setup the initial stack of the task. The stack is set exactly as
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97 expected by the portRESTORE_CONTEXT() macro. */
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99 /* First on the stack is the return address - which in this case is the
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100 start of the task. The offset is added to make the return address appear
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101 as it would within an IRQ ISR. */
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102 *pxTopOfStack = ( portSTACK_TYPE ) pxCode + portINSTRUCTION_SIZE;
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105 *pxTopOfStack = ( portSTACK_TYPE ) 0xaaaaaaaa; /* R14 */
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107 *pxTopOfStack = ( portSTACK_TYPE ) pxOriginalTOS; /* Stack used when task starts goes in R13. */
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109 *pxTopOfStack = ( portSTACK_TYPE ) 0x12121212; /* R12 */
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111 *pxTopOfStack = ( portSTACK_TYPE ) 0x11111111; /* R11 */
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113 *pxTopOfStack = ( portSTACK_TYPE ) 0x10101010; /* R10 */
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115 *pxTopOfStack = ( portSTACK_TYPE ) 0x09090909; /* R9 */
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117 *pxTopOfStack = ( portSTACK_TYPE ) 0x08080808; /* R8 */
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119 *pxTopOfStack = ( portSTACK_TYPE ) 0x07070707; /* R7 */
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121 *pxTopOfStack = ( portSTACK_TYPE ) 0x06060606; /* R6 */
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123 *pxTopOfStack = ( portSTACK_TYPE ) 0x05050505; /* R5 */
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125 *pxTopOfStack = ( portSTACK_TYPE ) 0x04040404; /* R4 */
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127 *pxTopOfStack = ( portSTACK_TYPE ) 0x03030303; /* R3 */
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129 *pxTopOfStack = ( portSTACK_TYPE ) 0x02020202; /* R2 */
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131 *pxTopOfStack = ( portSTACK_TYPE ) 0x01010101; /* R1 */
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134 /* When the task starts is will expect to find the function parameter in
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136 *pxTopOfStack = ( portSTACK_TYPE ) pvParameters; /* R0 */
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139 /* The status register is set for system mode, with interrupts enabled. */
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140 *pxTopOfStack = ( portSTACK_TYPE ) portINITIAL_SPSR;
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142 #ifdef THUMB_INTERWORK
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144 /* We want the task to start in thumb mode. */
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145 *pxTopOfStack |= portTHUMB_MODE_BIT;
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151 /* Interrupt flags cannot always be stored on the stack and will
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152 instead be stored in a variable, which is then saved as part of the
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154 *pxTopOfStack = portNO_CRITICAL_NESTING;
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156 return pxTopOfStack;
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158 /*-----------------------------------------------------------*/
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160 portBASE_TYPE xPortStartScheduler( void )
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162 extern void vPortISRStartFirstTask( void );
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164 /* Start the timer that generates the tick ISR. Interrupts are disabled
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166 prvSetupTimerInterrupt();
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168 /* Start the first task. */
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169 vPortISRStartFirstTask();
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171 /* Should not get here! */
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174 /*-----------------------------------------------------------*/
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176 void vPortEndScheduler( void )
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178 /* It is unlikely that the ARM port will require this function as there
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179 is nothing to return to. */
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181 /*-----------------------------------------------------------*/
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183 static void prvSetupTimerInterrupt( void )
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185 EIC_IRQInitTypeDef EIC_IRQInitStructure;
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186 TB_InitTypeDef TB_InitStructure;
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188 /* Setup the EIC for the TB. */
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189 EIC_IRQInitStructure.EIC_IRQChannelCmd = ENABLE;
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190 EIC_IRQInitStructure.EIC_IRQChannel = TB_IRQChannel;
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191 EIC_IRQInitStructure.EIC_IRQChannelPriority = 1;
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192 EIC_IRQInit(&EIC_IRQInitStructure);
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194 /* Setup the TB for the generation of the tick interrupt. */
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195 TB_InitStructure.TB_Mode = TB_Mode_Timing;
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196 TB_InitStructure.TB_CounterMode = TB_CounterMode_Down;
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197 TB_InitStructure.TB_Prescaler = portPRESCALE - 1;
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198 TB_InitStructure.TB_AutoReload = ( ( configCPU_CLOCK_HZ / ( portPRESCALE + 1 ) ) / configTICK_RATE_HZ ) + 1;
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199 TB_Init(&TB_InitStructure);
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201 /* Enable TB Update interrupt */
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202 TB_ITConfig(TB_IT_Update, ENABLE);
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204 /* Clear TB Update interrupt pending bit */
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205 TB_ClearITPendingBit(TB_IT_Update);
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210 /*-----------------------------------------------------------*/
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