2 FreeRTOS.org V5.1.2 - 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
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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 ***************************************************************************
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29 * Get the FreeRTOS eBook! See http://www.FreeRTOS.org/Documentation *
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31 * This is a concise, step by step, 'hands on' guide that describes both *
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32 * general multitasking concepts and FreeRTOS specifics. It presents and *
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33 * explains numerous examples that are written using the FreeRTOS API. *
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34 * Full source code for all the examples is provided in an accompanying *
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37 ***************************************************************************
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38 ***************************************************************************
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40 Please ensure to read the configuration and relevant port sections of the
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41 online documentation.
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43 http://www.FreeRTOS.org - Documentation, latest information, license and
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46 http://www.SafeRTOS.com - A version that is certified for use in safety
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49 http://www.OpenRTOS.com - Commercial support, development, porting,
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50 licensing and training services.
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53 /*-----------------------------------------------------------
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54 * Implementation of functions defined in portable.h for the ST STR75x ARM7
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56 *----------------------------------------------------------*/
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58 /* Library includes. */
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60 #include "75x_eic.h"
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62 /* Scheduler includes. */
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63 #include "FreeRTOS.h"
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66 /* Constants required to setup the initial stack. */
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67 #define portINITIAL_SPSR ( ( portSTACK_TYPE ) 0x1f ) /* System mode, ARM mode, interrupts enabled. */
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68 #define portTHUMB_MODE_BIT ( ( portSTACK_TYPE ) 0x20 )
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69 #define portINSTRUCTION_SIZE ( ( portSTACK_TYPE ) 4 )
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71 /* Constants required to handle critical sections. */
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72 #define portNO_CRITICAL_NESTING ( ( unsigned portLONG ) 0 )
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74 /* Prescale used on the timer clock when calculating the tick period. */
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75 #define portPRESCALE 20
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78 /*-----------------------------------------------------------*/
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80 /* Setup the TB to generate the tick interrupts. */
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81 static void prvSetupTimerInterrupt( void );
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83 /*-----------------------------------------------------------*/
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86 * Initialise the stack of a task to look exactly as if a call to
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87 * portSAVE_CONTEXT had been called.
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89 * See header file for description.
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91 portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
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93 portSTACK_TYPE *pxOriginalTOS;
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95 pxOriginalTOS = pxTopOfStack;
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97 /* Setup the initial stack of the task. The stack is set exactly as
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98 expected by the portRESTORE_CONTEXT() macro. */
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100 /* First on the stack is the return address - which in this case is the
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101 start of the task. The offset is added to make the return address appear
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102 as it would within an IRQ ISR. */
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103 *pxTopOfStack = ( portSTACK_TYPE ) pxCode + portINSTRUCTION_SIZE;
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106 *pxTopOfStack = ( portSTACK_TYPE ) 0xaaaaaaaa; /* R14 */
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108 *pxTopOfStack = ( portSTACK_TYPE ) pxOriginalTOS; /* Stack used when task starts goes in R13. */
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110 *pxTopOfStack = ( portSTACK_TYPE ) 0x12121212; /* R12 */
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112 *pxTopOfStack = ( portSTACK_TYPE ) 0x11111111; /* R11 */
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114 *pxTopOfStack = ( portSTACK_TYPE ) 0x10101010; /* R10 */
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116 *pxTopOfStack = ( portSTACK_TYPE ) 0x09090909; /* R9 */
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118 *pxTopOfStack = ( portSTACK_TYPE ) 0x08080808; /* R8 */
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120 *pxTopOfStack = ( portSTACK_TYPE ) 0x07070707; /* R7 */
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122 *pxTopOfStack = ( portSTACK_TYPE ) 0x06060606; /* R6 */
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124 *pxTopOfStack = ( portSTACK_TYPE ) 0x05050505; /* R5 */
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126 *pxTopOfStack = ( portSTACK_TYPE ) 0x04040404; /* R4 */
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128 *pxTopOfStack = ( portSTACK_TYPE ) 0x03030303; /* R3 */
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130 *pxTopOfStack = ( portSTACK_TYPE ) 0x02020202; /* R2 */
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132 *pxTopOfStack = ( portSTACK_TYPE ) 0x01010101; /* R1 */
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135 /* When the task starts is will expect to find the function parameter in
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137 *pxTopOfStack = ( portSTACK_TYPE ) pvParameters; /* R0 */
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140 /* The status register is set for system mode, with interrupts enabled. */
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141 *pxTopOfStack = ( portSTACK_TYPE ) portINITIAL_SPSR;
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143 #ifdef THUMB_INTERWORK
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145 /* We want the task to start in thumb mode. */
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146 *pxTopOfStack |= portTHUMB_MODE_BIT;
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152 /* Interrupt flags cannot always be stored on the stack and will
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153 instead be stored in a variable, which is then saved as part of the
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155 *pxTopOfStack = portNO_CRITICAL_NESTING;
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157 return pxTopOfStack;
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159 /*-----------------------------------------------------------*/
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161 portBASE_TYPE xPortStartScheduler( void )
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163 extern void vPortISRStartFirstTask( void );
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165 /* Start the timer that generates the tick ISR. Interrupts are disabled
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167 prvSetupTimerInterrupt();
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169 /* Start the first task. */
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170 vPortISRStartFirstTask();
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172 /* Should not get here! */
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175 /*-----------------------------------------------------------*/
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177 void vPortEndScheduler( void )
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179 /* It is unlikely that the ARM port will require this function as there
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180 is nothing to return to. */
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182 /*-----------------------------------------------------------*/
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184 static void prvSetupTimerInterrupt( void )
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186 EIC_IRQInitTypeDef EIC_IRQInitStructure;
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187 TB_InitTypeDef TB_InitStructure;
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189 /* Setup the EIC for the TB. */
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190 EIC_IRQInitStructure.EIC_IRQChannelCmd = ENABLE;
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191 EIC_IRQInitStructure.EIC_IRQChannel = TB_IRQChannel;
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192 EIC_IRQInitStructure.EIC_IRQChannelPriority = 1;
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193 EIC_IRQInit(&EIC_IRQInitStructure);
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195 /* Setup the TB for the generation of the tick interrupt. */
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196 TB_InitStructure.TB_Mode = TB_Mode_Timing;
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197 TB_InitStructure.TB_CounterMode = TB_CounterMode_Down;
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198 TB_InitStructure.TB_Prescaler = portPRESCALE - 1;
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199 TB_InitStructure.TB_AutoReload = ( ( configCPU_CLOCK_HZ / ( portPRESCALE + 1 ) ) / configTICK_RATE_HZ ) + 1;
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200 TB_Init(&TB_InitStructure);
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202 /* Enable TB Update interrupt */
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203 TB_ITConfig(TB_IT_Update, ENABLE);
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205 /* Clear TB Update interrupt pending bit */
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206 TB_ClearITPendingBit(TB_IT_Update);
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211 /*-----------------------------------------------------------*/
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