66 lines
2.0 KiB
C++
66 lines
2.0 KiB
C++
|
/**
|
||
|
|
* @file microsecond_timer_stm32.cpp
|
||
|
|
*
|
||
|
|
* A single upcounting timer (currently TIM5) is used as a single timebase both for time
|
||
|
|
* measurement and event scheduling. This helps reduce jitter by not making another time
|
||
|
|
* measurement at the time of scheduling.
|
||
|
|
*
|
||
|
|
* This implementation only works on stm32 because it sets hardware registers directly.
|
||
|
|
* ChibiOS doesn't support using timers in output compare mode, only PMW, so we have to
|
||
|
|
* manually configure the timer in outupt compare mode.
|
||
|
|
*
|
||
|
|
* @date Dec 1, 2020
|
||
|
|
* @author Matthew Kennedy, (c) 2012-2020
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include "global.h"
|
||
|
|
|
||
|
|
#if EFI_PROD_CODE && HAL_USE_PWM
|
||
|
|
|
||
|
|
#include "port_microsecond_timer.h"
|
||
|
|
|
||
|
|
void portSetHardwareSchedulerTimer(efitick_t nowNt, efitick_t setTimeNt) {
|
||
|
|
// This implementation doesn't need the current time, only the target time
|
||
|
|
UNUSED(nowNt);
|
||
|
|
|
||
|
|
pwm_lld_enable_channel(&SCHEDULER_PWM_DEVICE, 0, setTimeNt);
|
||
|
|
pwmEnableChannelNotificationI(&SCHEDULER_PWM_DEVICE, 0);
|
||
|
|
}
|
||
|
|
|
||
|
|
static void hwTimerCallback(PWMDriver*) {
|
||
|
|
pwmDisableChannelNotificationI(&SCHEDULER_PWM_DEVICE, 0);
|
||
|
|
portMicrosecondTimerCallback();
|
||
|
|
}
|
||
|
|
|
||
|
|
static constexpr PWMConfig timerConfig = {
|
||
|
|
SCHEDULER_TIMER_FREQ,
|
||
|
|
UINT32_MAX, // timer period = 2^32 counts
|
||
|
|
nullptr, // No update callback
|
||
|
|
{
|
||
|
|
{PWM_OUTPUT_DISABLED, hwTimerCallback}, // Channel 0 = timer callback, others unused
|
||
|
|
{PWM_OUTPUT_DISABLED, nullptr},
|
||
|
|
{PWM_OUTPUT_DISABLED, nullptr},
|
||
|
|
{PWM_OUTPUT_DISABLED, nullptr}
|
||
|
|
},
|
||
|
|
0, // CR1
|
||
|
|
0 // CR2
|
||
|
|
};
|
||
|
|
|
||
|
|
void portInitMicrosecondTimer() {
|
||
|
|
pwmStart(&SCHEDULER_PWM_DEVICE, &timerConfig);
|
||
|
|
|
||
|
|
// ChibiOS doesn't let you configure timers in output compare mode, only PWM mode.
|
||
|
|
// We want to be able to set the compare register without waiting for an update event
|
||
|
|
// (which would take 358 seconds at 12mhz timer speed), so we have to use normal upcounting
|
||
|
|
// output compare mode instead.
|
||
|
|
SCHEDULER_TIMER_DEVICE->CCMR1 = STM32_TIM_CCMR1_OC1M(1);
|
||
|
|
}
|
||
|
|
|
||
|
|
uint32_t getTimeNowLowerNt() {
|
||
|
|
// Using the same timer for measurement and scheduling improves
|
||
|
|
// precision and reduces jitter.
|
||
|
|
return SCHEDULER_TIMER_DEVICE->CNT;
|
||
|
|
}
|
||
|
|
|
||
|
|
#endif // EFI_PROD_CODE
|