/*
* timer2.c
*
* Created on: 2 Apr 2018
* Author: Mike
*/
#include "ch.h" // needs for all ChibiOS programs
#include "hal.h" // hardware abstraction layer header
#include "timer2.h"
#define MICROSECS_PULSE 4
// with a dwell angle of 45 degrees , 4 cylinders and a maximum RPM of 5000
// freq = 5000/60 * 2 = 166Hz. Because the breaker might bounce , we accept the
// first pulse longer than 1/300 of a second as being a proper closure .
// the TIM2 counter counts in 1uS increments,
#define BREAKER_COUNT_MIN (1E6/(MICROSECS_PULSE * 300))
#define COUNT_FROM_RPM(RPM) ((1E6/(MICROSECS_PULSE * 30 / (RPM ) )))
int16_t nominal = 0;
uint16_t halfRot;
int16_t phase10 = 100; // 10 degrees
volatile uint16_t sampleVar;
volatile uint16_t sampleRef;
volatile uint16_t lastSampleRef = 0;
volatile uint8_t refCount = 0;
volatile uint8_t varCount = 0;
volatile uint16_t samplePeriod = 0;
static signed phaseSamp = 0;
static uint8_t validPhaseSamp = 0;
int gainControl = 1000;
uint16_t rpm;
signed count;
signed delta;
void
recalcPhase ()
{
nominal = halfRot * (long) (phase10) / 3600;
}
void
adjustRPM (void)
{
if (rpm < 600)
rpm = 600;
if (rpm > 5000)
rpm = 5000;
}
uint16_t
setRPM (uint16_t rpm_)
{
if (rpm_ >= 600 && rpm_ < 6000)
{
rpm = rpm_;
adjustRPM ();
}
return halfRot;
}
uint16_t
getRPM (void)
{
return rpm;
}
signed
getDelta (void)
{
return delta;
}
signed
getCount (void)
{
return count;
}
void
setGain (int gain)
{
gainControl = gain;
}
void
processPhase (void)
{
// lpcl
const signed pdClip = 10000;
static signed pd;
if (validPhaseSamp)
{
chSysLock ();
pd = phaseSamp - nominal;
validPhaseSamp = 0;
chSysUnlock ();
if (pd > pdClip)
pd = pdClip;
if (pd < -pdClip)
pd = -pdClip;
}
else
return;
delta = pd;
static int sampleAverage = 0;
static int phaseAverage = 0;
const int freqScale = 16;
const int periodScale= 4; // 1/periodScale of difference between period measured and average is added to period.
const int phaseScale = 50;
// measure sample period devi
sampleAverage = sampleAverage + (samplePeriod *freqScale - sampleAverage) / periodScale;
int32_t arr;
// if(lock)
int intSample = sampleAverage / freqScale;
int deltaPd = pd / phaseScale;
if (deltaPd == 0)
{
if (pd > 0)
deltaPd = 1;
if (pd < 0)
deltaPd = -1;
}
arr = intSample + deltaPd;
// clamp values
if (arr > 65535)
arr = 65535;
if (arr < 1000)
arr = 1000;
count = arr;
TIM2->ARR = arr - 1;
nominal = intSample * (long) (phase10) / 3600;
float nomRPM = 30E6 / (MICROSECS_PULSE * arr);
rpm = nomRPM;
adjustRPM ();
}
// set the timing advance from reference in 0.1 degrees units
void
setAdvance (int16_t deg10)
{
phase10 = deg10;
}
// specialist timer setup :
// timer 2 is a reloading counter with a cycle period controlled by its ARR register.
// Just before terminal count it produces a pulse of 200 microseconds using its CCR1 count compare register,
// used to drive the strobe LED.
// Timer 3 is then used to count the time of the reload of Timer 2 via its Trigger Out being selected as reload.
// The time is latched in TIM3 CCR2
// and ignition pulses are latched on TIM3 CCR1, to allow it to be used in a PLL.
//
void
initTimers ()
{
rccEnableTIM2 (FALSE);
rccResetTIM2 ();
TIM2->PSC = 72 * MICROSECS_PULSE;
TIM2->ARR = 60000;
TIM2->CR1 = ~TIM_CR1_CKD & (TIM_CR1_CEN | TIM_CR1_ARPE);
/// pulse width 200 uS
TIM2->CCR1 = 200 / MICROSECS_PULSE;
TIM2->CCER = TIM_CCER_CC1E | TIM_CCER_CC1P; //enabled and active high
TIM2->CCMR1 = TIM_CCMR1_OC1M_0 | TIM_CCMR1_OC1M_1 | TIM_CCMR1_OC1M_2
| TIM_CCMR1_OC1PE;
TIM2->CR2 = TIM_CR2_MMS_1; // trigger out is 010 = update
rccEnableTIM3 (FALSE);
rccResetTIM3 ();
// TIM3 on the PA6 ... pins : remap code 00
AFIO->MAPR &= ~AFIO_MAPR_TIM3_REMAP;
TIM3->PSC = 72 * MICROSECS_PULSE;
TIM3->ARR = 0xFFFF;
TIM3->CCMR1 =
TIM_CCMR1_CC1S_0 /* | TIM_CCMR1_IC1F_0 | TIM_CCMR1_IC1F_1 | TIM_CCMR1_IC1F_2 */; // filter 16, input
// link TIM3 ITR2 to TIM2 reload
// use TS = 001 to make TRC from Tim2 TRIGGER
TIM3->SMCR &= ~(TIM_SMCR_TS_Msk);
TIM3->SMCR |= TIM_SMCR_TS_0; // select ITR2 as trigger source TRC
TIM3->CCMR1 |= TIM_CCMR1_CC2S_1 | TIM_CCMR1_CC2S_0; // The CC2S bits are 11, use TRC
TIM3->CCER = TIM_CCER_CC1E | TIM_CCER_CC2E;
TIM3->CR1 = ~TIM_CR1_CKD & (TIM_CR1_CEN | TIM_CR1_ARPE);
nvicEnableVector (TIM3_IRQn, 4);
TIM3->DIER |= TIM_DIER_CC1IE | TIM_DIER_CC2IE;
}
// timer 3 interrupt
void
VectorB4 (void)
{
if (TIM3->SR & TIM_SR_CC1IF)
{
uint16_t sample = TIM3->CCR1;
// if(sample-lastSampleRef > 1000 /*BREAKER_COUNT_MIN */)
{
samplePeriod = sample - sampleRef;
sampleRef = sample;
++refCount;
}
lastSampleRef = sample;
}
if (TIM3->SR & TIM_SR_CC2IF)
{
sampleVar = TIM3->CCR2;
++varCount;
}
if (refCount == 1 && varCount == 1)
{
if (sampleRef == sampleVar)
phaseSamp = 0;
else
{
uint16_t refToVar = sampleRef - sampleVar;
uint16_t varToRef = sampleVar - sampleRef;
if (refToVar < varToRef)
phaseSamp = refToVar;
else if (varToRef <= refToVar)
phaseSamp = -varToRef;
}
validPhaseSamp = 1;
refCount = 0;
varCount = 0;
}
// frequency error, should deal with by direct period measurement
if (refCount > 1 || varCount > 1)
{
refCount = 0;
varCount = 0;
}
}