20100923-V6.1.0-RC2/Demo/ColdFire_MCF52259_CodeWarrior/FreeRTOS_Tick_Setup.c

@@ -0,0 +1,140 @@
+/*
+    FreeRTOS V6.1.0 - Copyright (C) 2010 Real Time Engineers Ltd.
+
+    ***************************************************************************
+    *                                                                         *
+    * If you are:                                                             *
+    *                                                                         *
+    *    + New to FreeRTOS,                                                   *
+    *    + Wanting to learn FreeRTOS or multitasking in general quickly       *
+    *    + Looking for basic training,                                        *
+    *    + Wanting to improve your FreeRTOS skills and productivity           *
+    *                                                                         *
+    * then take a look at the FreeRTOS books - available as PDF or paperback  *
+    *                                                                         *
+    *        "Using the FreeRTOS Real Time Kernel - a Practical Guide"        *
+    *                  http://www.FreeRTOS.org/Documentation                  *
+    *                                                                         *
+    * A pdf reference manual is also available.  Both are usually delivered   *
+    * to your inbox within 20 minutes to two hours when purchased between 8am *
+    * and 8pm GMT (although please allow up to 24 hours in case of            *
+    * exceptional circumstances).  Thank you for your support!                *
+    *                                                                         *
+    ***************************************************************************
+
+    This file is part of the FreeRTOS distribution.
+
+    FreeRTOS is free software; you can redistribute it and/or modify it under
+    the terms of the GNU General Public License (version 2) as published by the
+    Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
+    ***NOTE*** The exception to the GPL is included to allow you to distribute
+    a combined work that includes FreeRTOS without being obliged to provide the
+    source code for proprietary components outside of the FreeRTOS kernel.
+    FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+    more details. You should have received a copy of the GNU General Public 
+    License and the FreeRTOS license exception along with FreeRTOS; if not it 
+    can be viewed here: http://www.freertos.org/a00114.html and also obtained 
+    by writing to Richard Barry, contact details for whom are available on the
+    FreeRTOS WEB site.
+
+    1 tab == 4 spaces!
+
+    http://www.FreeRTOS.org - Documentation, latest information, license and
+    contact details.
+
+    http://www.SafeRTOS.com - A version that is certified for use in safety
+    critical systems.
+
+    http://www.OpenRTOS.com - Commercial support, development, porting,
+    licensing and training services.
+*/
+
+#include "FreeRTOS.h"
+#include "task.h"
+
+__declspec(interrupt:0) void vPIT0InterruptHandler( void );
+
+/* Constants used to configure the interrupts. */
+#define portPRESCALE_VALUE			64
+#define portPRESCALE_REG_SETTING	( 5 << 8 )
+#define portPIT_INTERRUPT_ENABLED	( 0x08 )
+#define configPIT0_INTERRUPT_VECTOR	( 55 )
+
+/*
+ * FreeRTOS.org requires two interrupts - a tick interrupt generated from a
+ * timer source, and a spare interrupt vector used for context switching.
+ * The configuration below uses PIT0 for the former, and vector 16 for the
+ * latter.  **IF YOUR APPLICATION HAS BOTH OF THESE INTERRUPTS FREE THEN YOU DO
+ * NOT NEED TO CHANGE ANY OF THIS CODE** - otherwise instructions are provided
+ * here for using alternative interrupt sources.
+ *
+ * To change the tick interrupt source:
+ *
+ *	1) Modify vApplicationSetupInterrupts() below to be correct for whichever
+ *	peripheral is to be used to generate the tick interrupt.  The name of the
+ *  handler function (currently vPIT0InterruptHandler()) should also be updated
+ *  to indicate which peripheral is generating the interrupt.
+ *
+ *	2) Make sure the interrupt source is cleared within the interrupt handler function.
+ *  Currently vPIT0InterruptHandler() clears the PIT0 interrupt.
+ *
+ *  3) Update the vector table within mcf5225x_vectors.s to install the tick
+ *  interrupt handler in the correct vector position.
+ *
+ * To change the spare interrupt source:
+ *
+ *  1) Modify vApplicationSetupInterrupts() below to be correct for whichever
+ *  interrupt vector is to be used.  Make sure you use a spare interrupt on interrupt
+ *  controller 0, otherwise the register used to request context switches will also
+ *  require modification.
+ *
+ *  2) Change the definition of configYIELD_INTERRUPT_VECTOR within FreeRTOSConfig.h
+ *  to be correct for your chosen interrupt vector.
+ *
+ *  3) Update the vector table within mcf5225x_vectors.s to install the handler
+ *  _vPortYieldISR() in the correct vector position (by default vector number 16 is
+ *  used).
+ */
+void vApplicationSetupInterrupts( void )
+{
+const unsigned portSHORT usCompareMatchValue = ( ( configCPU_CLOCK_HZ / portPRESCALE_VALUE ) / configTICK_RATE_HZ );
+
+    /* Configure interrupt priority and level and unmask interrupt for PIT0. */
+    MCF_INTC0_ICR55 = ( 1 | ( configKERNEL_INTERRUPT_PRIORITY << 3 ) );
+    MCF_INTC0_IMRH &= ~( MCF_INTC_IMRH_INT_MASK55 );
+
+    /* Do the same for vector 63 (interrupt controller 0.  I don't think the
+    write to MCF_INTC0_IMRH is actually required here but is included for
+    completeness. */
+    MCF_INTC0_ICR16 = ( 0 | configKERNEL_INTERRUPT_PRIORITY << 3 );
+    MCF_INTC0_IMRL &= ~( MCF_INTC_IMRL_INT_MASK16 | 0x01 );
+
+    /* Configure PIT0 to generate the RTOS tick. */
+    MCF_PIT0_PCSR |= MCF_PIT_PCSR_PIF;
+    MCF_PIT0_PCSR = ( portPRESCALE_REG_SETTING | MCF_PIT_PCSR_PIE | MCF_PIT_PCSR_RLD | MCF_PIT_PCSR_EN );
+	MCF_PIT0_PMR = usCompareMatchValue;
+}
+/*-----------------------------------------------------------*/
+
+__declspec(interrupt:0) void vPIT0InterruptHandler( void )
+{
+unsigned portLONG ulSavedInterruptMask;
+
+	/* Clear the PIT0 interrupt. */
+	MCF_PIT0_PCSR |= MCF_PIT_PCSR_PIF;
+
+	/* Increment the RTOS tick. */
+	ulSavedInterruptMask = portSET_INTERRUPT_MASK_FROM_ISR();
+		vTaskIncrementTick();
+	portCLEAR_INTERRUPT_MASK_FROM_ISR( ulSavedInterruptMask );
+
+	/* If we are using the pre-emptive scheduler then also request a
+	context switch as incrementing the tick could have unblocked a task. */
+	#if configUSE_PREEMPTION == 1
+	{
+		taskYIELD();
+	}
+	#endif
+}