osd-contiki/cpu/stm32w108/hal/micro/cortexm3/system-timer.c

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2010-10-25 11:03:38 +02:00
/** @file hal/micro/cortexm3/system-timer.c
* @brief STM32W108 System Timer HAL functions.
*
* \b NOTE: The Sleep Timer count and compare registers are only 16 bits, but
* the counter and comparators themselves are actually 32bits. To deal with
* this, there are High ("H") and Low ("L") registers. The High register is
* the "action" register. When working with SLEEPTMR_CNT, reading the "H"
* register will return the upper 16 bits and simultaneously trigger the
* capture of the lower 16bits in the "L" register. The "L" register may then
* be read. When working with the SLEEPTMR_CMP registers, writing "L" will
* set a shadow register. Writing "H" will cause the value from the "H" write
* and the "L" shadow register to be combined and simultaneously loaded into
* the true 32bit comparator.
*
* <!--(C) COPYRIGHT 2010 STMicroelectronics. All rights reserved. -->
*/
#include PLATFORM_HEADER
#include "error.h"
#include "hal/micro/micro-common.h"
#include "hal/micro/cortexm3/micro-common.h"
#include "micro/system-timer.h"
//A simple flag used by internalSleepForQs to check that it has exited
//from sleep mode at the request of the expected timer interrupt.
static boolean sleepTimerInterruptOccurred = FALSE;
// halInternalStartSystemTimer() was moved to micro.c
/**
* Return a 16 bit real time clock value. With 1024 clock ticks per second,
* a single clock tick occurs every 0.9769625 milliseconds, and a rollover
* of the 16-bit timer occurs every 64 seconds.
*/
int16u halCommonGetInt16uMillisecondTick(void)
{
return (int16u)halCommonGetInt32uMillisecondTick();
}
int16u halCommonGetInt16uQuarterSecondTick(void)
{
return (int16u)(halCommonGetInt32uMillisecondTick() >> 8);
}
/**
* Return a 32 bit real time clock value. With 1024 clock ticks per second,
* a single clock tick occurs every 0.9769625 milliseconds, and a rollover
* of the 32-bit timer occurs approximately every 48.5 days.
*/
int32u halCommonGetInt32uMillisecondTick(void)
{
int32u time;
time = SLEEPTMR_CNTH<<16;
time |= SLEEPTMR_CNTL;
return time;
}
void halSleepTimerIsr(void)
{
//clear the second level interrupts
INT_SLEEPTMRFLAG = INT_SLEEPTMRWRAP | INT_SLEEPTMRCMPA | INT_SLEEPTMRCMPB;
//mark a sleep timer interrupt as having occurred
sleepTimerInterruptOccurred = TRUE;
}
#define CONVERT_QS_TO_TICKS(x) (x << 8)
#define CONVERT_TICKS_TO_QS(x) (x >> 8)
#define TIMER_MAX_QS 0x1000000 // = 4194304 seconds * 4 = 16777216
static StStatus internalSleepForQs(boolean useGpioWakeMask,
int32u *duration,
int32u gpioWakeBitMask)
{
StStatus status = ST_SUCCESS;
int32u sleepOverflowCount;
int32u remainder;
int32u startCount;
//There is really no reason to bother with a duration of 0qs
if(*duration==0) {
INTERRUPTS_ON();
return status;
}
ATOMIC(
//disable top-level interrupt while configuring
INT_CFGCLR = INT_SLEEPTMR;
//Our tick is calibrated to 1024Hz, giving a tick of 976.6us and an
//overflow of 4194304.0 seconds. Calculate the number of sleep overflows
//in the duration
sleepOverflowCount = (*duration)/TIMER_MAX_QS;
//calculate the remaining ticks
remainder = CONVERT_QS_TO_TICKS((*duration)%TIMER_MAX_QS);
//grab the starting sleep count
startCount = halCommonGetInt32uMillisecondTick();
sleepTimerInterruptOccurred = FALSE;
if(remainder) {
//set CMPA value
SLEEPTMR_CMPAL = (startCount+remainder)&0xFFFF;
SLEEPTMR_CMPAH = ((startCount+remainder)>>16)&0xFFFF;
//clear any stale interrupt flag and set the CMPA interrupt
INT_SLEEPTMRFLAG = INT_SLEEPTMRCMPA;
INT_SLEEPTMRCFG = INT_SLEEPTMRCMPA;
}
if(sleepOverflowCount) {
//set CMPB value
SLEEPTMR_CMPBL = startCount&0xFFFF;
SLEEPTMR_CMPBH = (startCount>>16)&0xFFFF;
//clear any stale interrupt flag and set the CMPB interrupt
//this will also disable the CMPA interrupt, since we only want to wake
//on overflows, not the remainder yet
INT_SLEEPTMRFLAG = INT_SLEEPTMRCMPB;
INT_SLEEPTMRCFG = INT_SLEEPTMRCMPB;
}
//enable top-level interrupt
INT_CFGSET = INT_SLEEPTMR;
)
while(*duration > 0) {
{
halSleepWithOptions(SLEEPMODE_WAKETIMER, gpioWakeBitMask);
}
INT_SLEEPTMRCFG = INT_SLEEPTMRCFG_RESET; //disable all SleepTMR interrupts
//If we didn't come out of sleep via a compare or overflow interrupt,
//it was an abnormal sleep interruption; report the event.
if(!sleepTimerInterruptOccurred) {
status = ST_SLEEP_INTERRUPTED;
//Update duration to account for how long last sleep was. Using the
//startCount variable is always valid because full timer wraps always
//return to this value and the remainder is an offset from this value.
//And since the duration is always reduced after each full timer wrap,
//we only need to calculate the final duration here.
*duration -= CONVERT_TICKS_TO_QS(halCommonGetInt32uMillisecondTick() -
startCount);
break;
} else {
if(sleepOverflowCount) {
sleepOverflowCount--;
*duration -= TIMER_MAX_QS;
} else {
*duration -= CONVERT_TICKS_TO_QS(remainder);
}
sleepTimerInterruptOccurred = FALSE;
if(sleepOverflowCount) {
//enable sleeping for a full timer wrap
INT_SLEEPTMRFLAG = INT_SLEEPTMRCMPB;
INT_SLEEPTMRCFG = INT_SLEEPTMRCMPB;
} else if(!sleepOverflowCount && (*duration>0)){
//enable sleeping for the remainder
INT_SLEEPTMRFLAG = INT_SLEEPTMRCMPA;
INT_SLEEPTMRCFG = INT_SLEEPTMRCMPA;
}
}
}
return status;
}
StStatus halSleepForQsWithOptions(int32u *duration, int32u gpioWakeBitMask)
{
return internalSleepForQs(TRUE, duration, gpioWakeBitMask);
}