/* | |
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. | |
*/ | |
/* Scheduler includes. */ | |
#include "FreeRTOS.h" | |
#include "task.h" | |
/*----------------------------------------------------------- | |
* Implementation of functions defined in portable.h for the MSP430 port. | |
*----------------------------------------------------------*/ | |
/* Constants required for hardware setup. The tick ISR runs off the ACLK, | |
not the MCLK. */ | |
#define portACLK_FREQUENCY_HZ ( ( portTickType ) 32768 ) | |
#define portINITIAL_CRITICAL_NESTING ( ( unsigned short ) 10 ) | |
#define portFLAGS_INT_ENABLED ( ( portSTACK_TYPE ) 0x08 ) | |
/* We require the address of the pxCurrentTCB variable, but don't want to know | |
any details of its type. */ | |
typedef void tskTCB; | |
extern volatile tskTCB * volatile pxCurrentTCB; | |
/* Each task maintains a count of the critical section nesting depth. Each | |
time a critical section is entered the count is incremented. Each time a | |
critical section is exited the count is decremented - with interrupts only | |
being re-enabled if the count is zero. | |
usCriticalNesting will get set to zero when the scheduler starts, but must | |
not be initialised to zero as this will cause problems during the startup | |
sequence. */ | |
volatile unsigned short usCriticalNesting = portINITIAL_CRITICAL_NESTING; | |
/*-----------------------------------------------------------*/ | |
/* | |
* Sets up the periodic ISR used for the RTOS tick. This uses timer 0, but | |
* could have alternatively used the watchdog timer or timer 1. | |
*/ | |
void vPortSetupTimerInterrupt( void ); | |
/*-----------------------------------------------------------*/ | |
/* | |
* Initialise the stack of a task to look exactly as if a call to | |
* portSAVE_CONTEXT had been called. | |
* | |
* See the header file portable.h. | |
*/ | |
portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters ) | |
{ | |
/* | |
Place a few bytes of known values on the bottom of the stack. | |
This is just useful for debugging and can be included if required. | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x1111; | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x2222; | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x3333; | |
pxTopOfStack--; | |
*/ | |
/* The msp430 automatically pushes the PC then SR onto the stack before | |
executing an ISR. We want the stack to look just as if this has happened | |
so place a pointer to the start of the task on the stack first - followed | |
by the flags we want the task to use when it starts up. */ | |
*pxTopOfStack = ( portSTACK_TYPE ) pxCode; | |
pxTopOfStack--; | |
*pxTopOfStack = portFLAGS_INT_ENABLED; | |
pxTopOfStack--; | |
/* Next the general purpose registers. */ | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x4444; | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x5555; | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x6666; | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x7777; | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x8888; | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x9999; | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0xaaaa; | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0xbbbb; | |
pxTopOfStack--; | |
/* When the task starts is will expect to find the function parameter in | |
R15. */ | |
*pxTopOfStack = ( portSTACK_TYPE ) pvParameters; | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0xdddd; | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0xeeee; | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0xffff; | |
pxTopOfStack--; | |
/* A variable is used to keep track of the critical section nesting. | |
This variable has to be stored as part of the task context and is | |
initially set to zero. */ | |
*pxTopOfStack = ( portSTACK_TYPE ) portNO_CRITICAL_SECTION_NESTING; | |
/* Return a pointer to the top of the stack we have generated so this can | |
be stored in the task control block for the task. */ | |
return pxTopOfStack; | |
} | |
/*-----------------------------------------------------------*/ | |
void vPortEndScheduler( void ) | |
{ | |
/* It is unlikely that the MSP430 port will get stopped. If required simply | |
disable the tick interrupt here. */ | |
} | |
/*-----------------------------------------------------------*/ | |
/* | |
* Hardware initialisation to generate the RTOS tick. This uses timer 0 | |
* but could alternatively use the watchdog timer or timer 1. | |
*/ | |
void vPortSetupTimerInterrupt( void ) | |
{ | |
/* Ensure the timer is stopped. */ | |
TACTL = 0; | |
/* Run the timer of the ACLK. */ | |
TACTL = TASSEL_1; | |
/* Clear everything to start with. */ | |
TACTL |= TACLR; | |
/* Set the compare match value according to the tick rate we want. */ | |
TACCR0 = portACLK_FREQUENCY_HZ / configTICK_RATE_HZ; | |
/* Enable the interrupts. */ | |
TACCTL0 = CCIE; | |
/* Start up clean. */ | |
TACTL |= TACLR; | |
/* Up mode. */ | |
TACTL |= MC_1; | |
} | |
/*-----------------------------------------------------------*/ | |