Change PWM updated to the latest version of Arduino PR #7231

This commit is contained in:
Stephan Hadinger 2020-05-08 17:52:24 +02:00
parent f66a0ee561
commit 87a1cd0ea0
4 changed files with 198 additions and 207 deletions

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@ -10,6 +10,7 @@
- Change HAss discovery by Federico Leoni (#8370)
- Change default PWM Frequency to 977 Hz from 223 Hz
- Change minimum PWM Frequency from 100 Hz to 40 Hz
- Change PWM updated to the latest version of Arduino PR #7231
### 8.2.0.5 20200425

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@ -47,29 +47,23 @@
extern "C" {
// Internal-only calls, not for applications
extern void _setPWMPeriodCC(uint32_t cc);
extern void _setPWMFreq(uint32_t freq);
extern bool _stopPWM(int pin);
extern bool _setPWM(int pin, uint32_t cc);
extern bool _setPWM(int pin, uint32_t val, uint32_t range);
extern int startWaveformClockCycles(uint8_t pin, uint32_t timeHighCycles, uint32_t timeLowCycles, uint32_t runTimeCycles);
// Maximum delay between IRQs
#define MAXIRQUS (10000)
// Set/clear GPIO 0-15 by bitmask
#define SetGPIO(a) do { GPOS = a; } while (0)
#define ClearGPIO(a) do { GPOC = a; } while (0)
// Waveform generator can create tones, PWM, and servos
typedef struct {
uint32_t nextServiceCycle; // ESP cycle timer when a transition required
uint32_t expiryCycle; // For time-limited waveform, the cycle when this waveform must stop
uint32_t timeHighCycles; // Currently running waveform period
uint32_t timeHighCycles; // Actual running waveform period (adjusted using desiredCycles)
uint32_t timeLowCycles; //
uint32_t desiredHighCycles; // Currently running waveform period
uint32_t desiredLowCycles; //
uint32_t gotoTimeHighCycles; // Copied over on the next period to preserve phase
uint32_t gotoTimeLowCycles; //
uint32_t lastEdge; //
uint32_t desiredHighCycles; // Ideal waveform period to drive the error signal
uint32_t desiredLowCycles; //
uint32_t lastEdge; // Cycle when this generator last changed
} Waveform;
class WVFState {
@ -82,7 +76,7 @@ public:
uint32_t waveformToEnable = 0; // Message to the NMI handler to start a waveform on a inactive pin
uint32_t waveformToDisable = 0; // Message to the NMI handler to disable a pin from waveform generation
int32_t waveformToChange = -1;
uint32_t waveformToChange = 0; // Mask of pin to change. One bit set in main app, cleared when effected in the NMI
uint32_t waveformNewHigh = 0;
uint32_t waveformNewLow = 0;
@ -91,8 +85,8 @@ public:
// Optimize the NMI inner loop by keeping track of the min and max GPIO that we
// are generating. In the common case (1 PWM) these may be the same pin and
// we can avoid looking at the other pins.
int startPin = 0;
int endPin = 0;
uint16_t startPin = 0;
uint16_t endPin = 0;
};
static WVFState wvfState;
@ -107,7 +101,7 @@ static WVFState wvfState;
static ICACHE_RAM_ATTR void timer1Interrupt();
static bool timerRunning = false;
static void initTimer() {
static __attribute__((noinline)) void initTimer() {
if (!timerRunning) {
timer1_disable();
ETS_FRC_TIMER1_INTR_ATTACH(NULL, NULL);
@ -138,21 +132,22 @@ static ICACHE_RAM_ATTR void forceTimerInterrupt() {
constexpr int maxPWMs = 8;
// PWM machine state
typedef struct {
typedef struct PWMState {
uint32_t mask; // Bitmask of active pins
uint32_t cnt; // How many entries
uint32_t idx; // Where the state machine is along the list
uint8_t pin[maxPWMs + 1];
uint32_t delta[maxPWMs + 1];
uint32_t nextServiceCycle; // Clock cycle for next step
struct PWMState *pwmUpdate; // Set by main code, cleared by ISR
} PWMState;
static PWMState pwmState;
static PWMState *pwmUpdate = nullptr; // Set by main code, cleared by ISR
static uint32_t pwmPeriod = microsecondsToClockCycles(1000000UL) / 1000;
static uint32_t _pwmPeriod = microsecondsToClockCycles(1000000UL) / 1000;
// If there are no more scheduled activities, shut down Timer 1.
// Otherwise, do nothing.
static ICACHE_RAM_ATTR void disableIdleTimer() {
if (timerRunning && !wvfState.waveformEnabled && !pwmState.cnt && !wvfState.timer1CB) {
ETS_FRC_TIMER1_NMI_INTR_ATTACH(NULL);
@ -162,62 +157,78 @@ static ICACHE_RAM_ATTR void disableIdleTimer() {
}
}
// Notify the NMI that a new PWM state is available through the mailbox.
// Wait for mailbox to be emptied (either busy or delay() as needed)
static ICACHE_RAM_ATTR void _notifyPWM(PWMState *p, bool idle) {
p->pwmUpdate = nullptr;
pwmState.pwmUpdate = p;
MEMBARRIER();
forceTimerInterrupt();
while (pwmState.pwmUpdate) {
if (idle) {
delay(0);
}
MEMBARRIER();
}
}
static void _addPWMtoList(PWMState &p, int pin, uint32_t val, uint32_t range);
// Called when analogWriteFreq() changed to update the PWM total period
void _setPWMPeriodCC(uint32_t cc) {
if (cc == pwmPeriod) {
return;
void _setPWMFreq(uint32_t freq) {
// Convert frequency into clock cycles
uint32_t cc = microsecondsToClockCycles(1000000UL) / freq;
// Simple static adjustment to bring period closer to requested due to overhead
#if F_CPU == 80000000
cc -= microsecondsToClockCycles(2);
#else
cc -= microsecondsToClockCycles(1);
#endif
if (cc == _pwmPeriod) {
return; // No change
}
_pwmPeriod = cc;
if (pwmState.cnt) {
// Adjust any running ones to the best of our abilities by scaling them
// Used FP math for speed and code size
uint64_t oldCC64p0 = ((uint64_t)pwmPeriod);
uint64_t newCC64p16 = ((uint64_t)cc) << 16;
uint64_t ratio64p16 = (newCC64p16 / oldCC64p0);
PWMState p; // The working copy since we can't edit the one in use
p = pwmState;
uint32_t ttl = 0;
for (uint32_t i = 0; i < p.cnt; i++) {
uint64_t val64p16 = ((uint64_t)p.delta[i]) << 16;
uint64_t newVal64p32 = val64p16 * ratio64p16;
p.delta[i] = newVal64p32 >> 32;
ttl += p.delta[i];
p.cnt = 0;
for (uint32_t i = 0; i < pwmState.cnt; i++) {
auto pin = pwmState.pin[i];
_addPWMtoList(p, pin, wvfState.waveform[pin].desiredHighCycles, wvfState.waveform[pin].desiredLowCycles);
}
p.delta[p.cnt] = cc - ttl; // Final cleanup exactly cc total cycles
// Update and wait for mailbox to be emptied
pwmUpdate = &p;
MEMBARRIER();
forceTimerInterrupt();
while (pwmUpdate) {
delay(0);
// No mem barrier. The external function call guarantees it's re-read
}
initTimer();
_notifyPWM(&p, true);
disableIdleTimer();
}
pwmPeriod = cc;
}
// Helper routine to remove an entry from the state machine
static ICACHE_RAM_ATTR void _removePWMEntry(int pin, PWMState *p) {
uint32_t i;
// Find the pin to pull out...
for (i = 0; p->pin[i] != pin; i++) { /* no-op */ }
auto delta = p->delta[i];
// Add the removed previous pin delta to preserve absolute position
p->delta[i+1] += delta;
// Move everything back one
for (i++; i <= p->cnt; i++) {
p->pin[i-1] = p->pin[i];
p->delta[i-1] = p->delta[i];
// and clean up any marked-off entries
static void _cleanAndRemovePWM(PWMState *p, int pin) {
uint32_t leftover = 0;
uint32_t in, out;
for (in = 0, out = 0; in < p->cnt; in++) {
if ((p->pin[in] != pin) && (p->mask & (1<<p->pin[in]))) {
p->pin[out] = p->pin[in];
p->delta[out] = p->delta[in] + leftover;
leftover = 0;
out++;
} else {
leftover += p->delta[in];
p->mask &= ~(1<<p->pin[in]);
}
}
// Remove the pin from the active list
p->mask &= ~(1<<pin);
p->cnt--;
p->cnt = out;
// Final pin is never used: p->pin[out] = 0xff;
p->delta[out] = p->delta[in] + leftover;
}
// Called by analogWrite(0/100%) to disable PWM on a specific pin
// Disable PWM on a specific pin (i.e. when a digitalWrite or analogWrite(0%/100%))
ICACHE_RAM_ATTR bool _stopPWM(int pin) {
if (!((1<<pin) & pwmState.mask)) {
return false; // Pin not actually active
@ -225,67 +236,88 @@ ICACHE_RAM_ATTR bool _stopPWM(int pin) {
PWMState p; // The working copy since we can't edit the one in use
p = pwmState;
_removePWMEntry(pin, &p);
// Update and wait for mailbox to be emptied
pwmUpdate = &p;
MEMBARRIER();
forceTimerInterrupt();
while (pwmUpdate) {
MEMBARRIER();
/* Busy wait, could be in ISR */
// In _stopPWM we just clear the mask but keep everything else
// untouched to save IRAM. The main startPWM will handle cleanup.
p.mask &= ~(1<<pin);
if (!p.mask) {
// If all have been stopped, then turn PWM off completely
p.cnt = 0;
}
// Update and wait for mailbox to be emptied, no delay (could be in ISR)
_notifyPWM(&p, false);
// Possibly shut down the timer completely if we're done
disableIdleTimer();
return true;
}
// Called by analogWrite(1...99%) to set the PWM duty in clock cycles
bool _setPWM(int pin, uint32_t cc) {
stopWaveform(pin);
PWMState p; // Working copy
p = pwmState;
// Get rid of any entries for this pin
if ((1<<pin) & p.mask) {
_removePWMEntry(pin, &p);
static void _addPWMtoList(PWMState &p, int pin, uint32_t val, uint32_t range) {
// Stash the val and range so we can re-evaluate the fraction
// should the user change PWM frequency. This allows us to
// give as great a precision as possible. We know by construction
// that the waveform for this pin will be inactive so we can borrow
// memory from that structure.
wvfState.waveform[pin].desiredHighCycles = val; // Numerator == high
wvfState.waveform[pin].desiredLowCycles = range; // Denominator == low
uint32_t cc = (_pwmPeriod * val) / range;
if (cc == 0) {
_stopPWM(pin);
digitalWrite(pin, LOW);
return;
} else if (cc >= _pwmPeriod) {
_stopPWM(pin);
digitalWrite(pin, HIGH);
return;
}
// And add it to the list, in order
if (p.cnt >= maxPWMs) {
return false; // No space left
} else if (p.cnt == 0) {
if (p.cnt == 0) {
// Starting up from scratch, special case 1st element and PWM period
p.pin[0] = pin;
p.delta[0] = cc;
p.pin[1] = 0xff;
p.delta[1] = pwmPeriod - cc;
p.cnt = 1;
p.mask = 1<<pin;
// Final pin is never used: p.pin[1] = 0xff;
p.delta[1] = _pwmPeriod - cc;
} else {
uint32_t ttl=0;
uint32_t ttl = 0;
uint32_t i;
// Skip along until we're at the spot to insert
for (i=0; (i <= p.cnt) && (ttl + p.delta[i] < cc); i++) {
ttl += p.delta[i];
}
// Shift everything out by one to make space for new edge
memmove(&p.pin[i + 1], &p.pin[i], (1 + p.cnt - i) * sizeof(p.pin[0]));
memmove(&p.delta[i + 1], &p.delta[i], (1 + p.cnt - i) * sizeof(p.delta[0]));
for (int32_t j = p.cnt; j >= (int)i; j--) {
p.pin[j + 1] = p.pin[j];
p.delta[j + 1] = p.delta[j];
}
int off = cc - ttl; // The delta from the last edge to the one we're inserting
p.pin[i] = pin;
p.delta[i] = off; // Add the delta to this new pin
p.delta[i + 1] -= off; // And subtract it from the follower to keep sum(deltas) constant
p.cnt++;
p.mask |= 1<<pin;
}
p.cnt++;
p.mask |= 1<<pin;
}
// Called by analogWrite(1...99%) to set the PWM duty in clock cycles
bool _setPWM(int pin, uint32_t val, uint32_t range) {
stopWaveform(pin);
PWMState p; // Working copy
p = pwmState;
// Get rid of any entries for this pin
_cleanAndRemovePWM(&p, pin);
// And add it to the list, in order
if (p.cnt >= maxPWMs) {
return false; // No space left
}
_addPWMtoList(p, pin, val, range);
// Set mailbox and wait for ISR to copy it over
pwmUpdate = &p;
MEMBARRIER();
initTimer();
forceTimerInterrupt();
while (pwmUpdate) {
delay(0);
}
_notifyPWM(&p, true);
disableIdleTimer();
return true;
}
@ -311,22 +343,22 @@ int startWaveformClockCycles(uint8_t pin, uint32_t timeHighCycles, uint32_t time
uint32_t mask = 1<<pin;
MEMBARRIER();
if (wvfState.waveformEnabled & mask) {
wvfState.waveformNewHigh = timeHighCycles;
wvfState.waveformNewLow = timeLowCycles;
MEMBARRIER();
wvfState.waveformToChange = pin;
while (wvfState.waveformToChange >= 0) {
// Make sure no waveform changes are waiting to be applied
while (wvfState.waveformToChange) {
delay(0); // Wait for waveform to update
// No mem barrier here, the call to a global function implies global state updated
}
wvfState.waveformNewHigh = timeHighCycles;
wvfState.waveformNewLow = timeLowCycles;
MEMBARRIER();
wvfState.waveformToChange = mask;
// The waveform will be updated some time in the future on the next period for the signal
} else { // if (!(wvfState.waveformEnabled & mask)) {
wave->timeHighCycles = timeHighCycles;
wave->desiredHighCycles = timeHighCycles;
wave->timeLowCycles = timeLowCycles;
wave->desiredHighCycles = wave->timeHighCycles;
wave->desiredLowCycles = wave->timeLowCycles;
wave->desiredLowCycles = timeLowCycles;
wave->lastEdge = 0;
wave->gotoTimeHighCycles = wave->timeHighCycles;
wave->gotoTimeLowCycles = wave->timeLowCycles; // Actually set the pin high or low in the IRQ service to guarantee times
wave->nextServiceCycle = ESP.getCycleCount() + microsecondsToClockCycles(1);
wvfState.waveformToEnable |= mask;
MEMBARRIER();
@ -355,10 +387,10 @@ void setTimer1Callback(uint32_t (*fn)()) {
// Speed critical bits
#pragma GCC optimize ("O2")
// Normally would not want two copies like this, but due to different
// optimization levels the inline attribute gets lost if we try the
// other version.
static inline ICACHE_RAM_ATTR uint32_t GetCycleCountIRQ() {
uint32_t ccount;
__asm__ __volatile__("rsr %0,ccount":"=a"(ccount));
@ -380,8 +412,13 @@ int ICACHE_RAM_ATTR stopWaveform(uint8_t pin) {
}
// If user sends in a pin >16 but <32, this will always point to a 0 bit
// If they send >=32, then the shift will result in 0 and it will also return false
if (wvfState.waveformEnabled & (1UL << pin)) {
wvfState.waveformToDisable = 1UL << pin;
uint32_t mask = 1<<pin;
if (wvfState.waveformEnabled & mask) {
wvfState.waveformToDisable = mask;
// Cancel any pending updates for this waveform, too.
if (wvfState.waveformToChange & mask) {
wvfState.waveformToChange = 0;
}
forceTimerInterrupt();
while (wvfState.waveformToDisable) {
MEMBARRIER(); // If it wasn't written yet, it has to be by now
@ -407,15 +444,6 @@ int ICACHE_RAM_ATTR stopWaveform(uint8_t pin) {
#define adjust(x) ((x) >> (turbo ? 0 : 1))
#endif
#define ENABLE_ADJUST // Adjust takes 36 bytes
#define ENABLE_FEEDBACK // Feedback costs 68 bytes
#define ENABLE_PWM // PWM takes 160 bytes
#ifndef ENABLE_ADJUST
#undef adjust
#define adjust(x) (x)
#endif
static ICACHE_RAM_ATTR void timer1Interrupt() {
// Flag if the core is at 160 MHz, for use by adjust()
@ -435,19 +463,12 @@ static ICACHE_RAM_ATTR void timer1Interrupt() {
wvfState.startPin = __builtin_ffs(wvfState.waveformEnabled) - 1;
// Find the last bit by subtracting off GCC's count-leading-zeros (no offset in this one)
wvfState.endPin = 32 - __builtin_clz(wvfState.waveformEnabled);
#ifdef ENABLE_PWM
} else if (!pwmState.cnt && pwmUpdate) {
} else if (!pwmState.cnt && pwmState.pwmUpdate) {
// Start up the PWM generator by copying from the mailbox
pwmState.cnt = 1;
pwmState.idx = 1; // Ensure copy this cycle, cause it to start at t=0
pwmState.nextServiceCycle = GetCycleCountIRQ(); // Do it this loop!
// No need for mem barrier here. Global must be written by IRQ exit
#endif
} else if (wvfState.waveformToChange >= 0) {
wvfState.waveform[wvfState.waveformToChange].gotoTimeHighCycles = wvfState.waveformNewHigh;
wvfState.waveform[wvfState.waveformToChange].gotoTimeLowCycles = wvfState.waveformNewLow;
wvfState.waveformToChange = -1;
// No need for memory barrier here. The global has to be written before exit the ISR.
}
bool done = false;
@ -455,35 +476,32 @@ static ICACHE_RAM_ATTR void timer1Interrupt() {
do {
nextEventCycles = microsecondsToClockCycles(MAXIRQUS);
#ifdef ENABLE_PWM
// PWM state machine implementation
if (pwmState.cnt) {
uint32_t now = GetCycleCountIRQ();
int32_t cyclesToGo = pwmState.nextServiceCycle - now;
int32_t cyclesToGo = pwmState.nextServiceCycle - GetCycleCountIRQ();
if (cyclesToGo < 0) {
if (pwmState.idx == pwmState.cnt) { // Start of pulses, possibly copy new
if (pwmUpdate) {
// Do the memory copy from temp to global and clear mailbox
pwmState = *(PWMState*)pwmUpdate;
pwmUpdate = nullptr;
}
GPOS = pwmState.mask; // Set all active pins high
// GPIO16 isn't the same as the others
if (pwmState.mask & (1<<16)) {
GP16O = 1;
}
pwmState.idx = 0;
if (pwmState.pwmUpdate) {
// Do the memory copy from temp to global and clear mailbox
pwmState = *(PWMState*)pwmState.pwmUpdate;
}
GPOS = pwmState.mask; // Set all active pins high
if (pwmState.mask & (1<<16)) {
GP16O = 1;
}
pwmState.idx = 0;
} else {
do {
// Drop the pin at this edge
GPOC = 1<<pwmState.pin[pwmState.idx];
// GPIO16 still needs manual work
if (pwmState.pin[pwmState.idx] == 16) {
GP16O = 0;
}
pwmState.idx++;
// Any other pins at this same PWM value will have delta==0, drop them too.
} while (pwmState.delta[pwmState.idx] == 0);
do {
// Drop the pin at this edge
if (pwmState.mask & (1<<pwmState.pin[pwmState.idx])) {
GPOC = 1<<pwmState.pin[pwmState.idx];
if (pwmState.pin[pwmState.idx] == 16) {
GP16O = 0;
}
}
pwmState.idx++;
// Any other pins at this same PWM value will have delta==0, drop them too.
} while (pwmState.delta[pwmState.idx] == 0);
}
// Preserve duty cycle over PWM period by using now+xxx instead of += delta
cyclesToGo = adjust(pwmState.delta[pwmState.idx]);
@ -491,7 +509,6 @@ static ICACHE_RAM_ATTR void timer1Interrupt() {
}
nextEventCycles = min_u32(nextEventCycles, cyclesToGo);
}
#endif
for (auto i = wvfState.startPin; i <= wvfState.endPin; i++) {
uint32_t mask = 1<<i;
@ -509,12 +526,11 @@ static ICACHE_RAM_ATTR void timer1Interrupt() {
int32_t expiryToGo = wave->expiryCycle - now;
if (expiryToGo < 0) {
// Done, remove!
wvfState.waveformEnabled &= ~mask;
if (i == 16) {
GP16O = 0;
} else {
ClearGPIO(mask);
}
}
GPOC = mask;
wvfState.waveformEnabled &= ~mask;
continue;
}
}
@ -528,39 +544,33 @@ static ICACHE_RAM_ATTR void timer1Interrupt() {
wvfState.waveformState ^= mask;
if (wvfState.waveformState & mask) {
if (i == 16) {
GP16O = 1; // GPIO16 write slow as it's RMW
} else {
SetGPIO(mask);
GP16O = 1;
}
if (wave->gotoTimeHighCycles) {
GPOS = mask;
if (wvfState.waveformToChange & mask) {
// Copy over next full-cycle timings
wave->timeHighCycles = wave->gotoTimeHighCycles;
wave->desiredHighCycles = wave->gotoTimeHighCycles;
wave->timeLowCycles = wave->gotoTimeLowCycles;
wave->desiredLowCycles = wave->gotoTimeLowCycles;
wave->gotoTimeHighCycles = 0;
} else {
#ifdef ENABLE_FEEDBACK
if (wave->lastEdge) {
desired = wave->desiredLowCycles;
timeToUpdate = &wave->timeLowCycles;
}
wave->timeHighCycles = wvfState.waveformNewHigh;
wave->desiredHighCycles = wvfState.waveformNewHigh;
wave->timeLowCycles = wvfState.waveformNewLow;
wave->desiredLowCycles = wvfState.waveformNewLow;
wave->lastEdge = 0;
wvfState.waveformToChange = 0;
}
if (wave->lastEdge) {
desired = wave->desiredLowCycles;
timeToUpdate = &wave->timeLowCycles;
}
#endif
nextEdgeCycles = wave->timeHighCycles;
} else {
if (i == 16) {
GP16O = 0; // GPIO16 write slow as it's RMW
} else {
ClearGPIO(mask);
GP16O = 0;
}
#ifdef ENABLE_FEEDBACK
GPOC = mask;
desired = wave->desiredHighCycles;
timeToUpdate = &wave->timeHighCycles;
#endif
nextEdgeCycles = wave->timeLowCycles;
}
#ifdef ENABLE_FEEDBACK
if (desired) {
desired = adjust(desired);
int32_t err = desired - (now - wave->lastEdge);
@ -569,7 +579,6 @@ static ICACHE_RAM_ATTR void timer1Interrupt() {
*timeToUpdate += err;
}
}
#endif
nextEdgeCycles = adjust(nextEdgeCycles);
wave->nextServiceCycle = now + nextEdgeCycles;
nextEventCycles = min_u32(nextEventCycles, nextEdgeCycles);
@ -599,7 +608,6 @@ static ICACHE_RAM_ATTR void timer1Interrupt() {
// Do it here instead of global function to save time and because we know it's edge-IRQ
T1L = nextEventCycles >> (turbo ? 1 : 0);
TEIE |= TEIE1; // Edge int enable
}
};

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@ -34,9 +34,9 @@
extern "C" {
// Internal-only calls, not for applications
extern void _setPWMPeriodCC(uint32_t cc);
extern void _setPWMFreq(uint32_t freq);
extern bool _stopPWM(int pin);
extern bool _setPWM(int pin, uint32_t cc);
extern bool _setPWM(int pin, uint32_t val, uint32_t range);
extern void resetPins();
volatile uint32_t* const esp8266_gpioToFn[16] PROGMEM = { &GPF0, &GPF1, &GPF2, &GPF3, &GPF4, &GPF5, &GPF6, &GPF7, &GPF8, &GPF9, &GPF10, &GPF11, &GPF12, &GPF13, &GPF14, &GPF15 };

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@ -29,13 +29,11 @@
extern "C" {
// Internal-only calls, not for applications
extern void _setPWMPeriodCC(uint32_t cc);
extern void _setPWMFreq(uint32_t freq);
extern bool _stopPWM(int pin);
extern bool _setPWM(int pin, uint32_t cc);
extern bool _setPWM(int pin, uint32_t val, uint32_t range);
static uint32_t analogMap = 0;
static int32_t analogScale = PWMRANGE;
static uint16_t analogFreq = 1000;
extern void __analogWriteRange(uint32_t range) {
if (range > 0) {
@ -43,17 +41,15 @@ extern void __analogWriteRange(uint32_t range) {
}
}
extern void __analogWriteFreq(uint32_t freq) {
if (freq < 40) { // Arduino sets a minimum of 100Hz, waiting for them to change this one.
analogFreq = 40;
if (freq < 40) {
freq = 40;
} else if (freq > 60000) {
analogFreq = 60000;
freq = 60000;
} else {
analogFreq = freq;
freq = freq;
}
uint32_t analogPeriod = microsecondsToClockCycles(1000000UL) / analogFreq;
_setPWMPeriodCC(analogPeriod);
_setPWMFreq(freq);
}
extern void __analogWrite(uint8_t pin, int val) {
@ -61,28 +57,14 @@ extern void __analogWrite(uint8_t pin, int val) {
return;
}
uint32_t analogPeriod = microsecondsToClockCycles(1000000UL) / analogFreq;
_setPWMPeriodCC(analogPeriod);
if (val < 0) {
val = 0;
} else if (val > analogScale) {
val = analogScale;
}
analogMap &= ~(1 << pin);
uint32_t high = (analogPeriod * val) / analogScale;
uint32_t low = analogPeriod - high;
pinMode(pin, OUTPUT);
if (low == 0) {
_stopPWM(pin);
digitalWrite(pin, HIGH);
} else if (high == 0) {
_stopPWM(pin);
digitalWrite(pin, LOW);
} else {
_setPWM(pin, high);
analogMap |= (1 << pin);
}
_setPWM(pin, val, analogScale);
}
extern void analogWrite(uint8_t pin, int val) __attribute__((weak, alias("__analogWrite")));