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/**
* Marlin 3D Printer Firmware
* Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
*
* Based on Sprinter and grbl.
* Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*
*/
#ifdef __AVR__
#include "../../inc/MarlinConfigPre.h"
#if NEEDS_HARDWARE_PWM // Specific meta-flag for features that mandate PWM
#include "HAL.h"
struct Timer {
volatile uint8_t* TCCRnQ[3]; // max 3 TCCR registers per timer
volatile uint16_t* OCRnQ[3]; // max 3 OCR registers per timer
volatile uint16_t* ICRn; // max 1 ICR register per timer
uint8_t n; // the timer number [0->5]
uint8_t q; // the timer output [0->2] (A->C)
};
/**
* get_pwm_timer
* Get the timer information and register of the provided pin.
* Return a Timer struct containing this information.
* Used by set_pwm_frequency, set_pwm_duty
*/
Timer get_pwm_timer(const pin_t pin) {
uint8_t q = 0;
switch (digitalPinToTimer(pin)) {
// Protect reserved timers (TIMER0 & TIMER1)
#ifdef TCCR0A
#if !AVR_AT90USB1286_FAMILY
case TIMER0A:
#endif
case TIMER0B:
#endif
#ifdef TCCR1A
case TIMER1A: case TIMER1B:
#endif
break;
#if defined(TCCR2) || defined(TCCR2A)
#ifdef TCCR2
case TIMER2: {
Timer timer = {
/*TCCRnQ*/ { &TCCR2, nullptr, nullptr },
/*OCRnQ*/ { (uint16_t*)&OCR2, nullptr, nullptr },
/*ICRn*/ nullptr,
/*n, q*/ 2, 0
};
}
#elif defined(TCCR2A)
#if ENABLED(USE_OCR2A_AS_TOP)
case TIMER2A: break; // protect TIMER2A
case TIMER2B: {
Timer timer = {
/*TCCRnQ*/ { &TCCR2A, &TCCR2B, nullptr },
/*OCRnQ*/ { (uint16_t*)&OCR2A, (uint16_t*)&OCR2B, nullptr },
/*ICRn*/ nullptr,
/*n, q*/ 2, 1
};
return timer;
}
#else
case TIMER2B: ++q;
case TIMER2A: {
Timer timer = {
/*TCCRnQ*/ { &TCCR2A, &TCCR2B, nullptr },
/*OCRnQ*/ { (uint16_t*)&OCR2A, (uint16_t*)&OCR2B, nullptr },
/*ICRn*/ nullptr,
2, q
};
return timer;
}
#endif
#endif
#endif
#ifdef OCR3C
case TIMER3C: ++q;
case TIMER3B: ++q;
case TIMER3A: {
Timer timer = {
/*TCCRnQ*/ { &TCCR3A, &TCCR3B, &TCCR3C },
/*OCRnQ*/ { &OCR3A, &OCR3B, &OCR3C },
/*ICRn*/ &ICR3,
/*n, q*/ 3, q
};
return timer;
}
#elif defined(OCR3B)
case TIMER3B: ++q;
case TIMER3A: {
Timer timer = {
/*TCCRnQ*/ { &TCCR3A, &TCCR3B, nullptr },
/*OCRnQ*/ { &OCR3A, &OCR3B, nullptr },
/*ICRn*/ &ICR3,
/*n, q*/ 3, q
};
return timer;
}
#endif
#ifdef TCCR4A
case TIMER4C: ++q;
case TIMER4B: ++q;
case TIMER4A: {
Timer timer = {
/*TCCRnQ*/ { &TCCR4A, &TCCR4B, &TCCR4C },
/*OCRnQ*/ { &OCR4A, &OCR4B, &OCR4C },
/*ICRn*/ &ICR4,
/*n, q*/ 4, q
};
return timer;
}
#endif
#ifdef TCCR5A
case TIMER5C: ++q;
case TIMER5B: ++q;
case TIMER5A: {
Timer timer = {
/*TCCRnQ*/ { &TCCR5A, &TCCR5B, &TCCR5C },
/*OCRnQ*/ { &OCR5A, &OCR5B, &OCR5C },
/*ICRn*/ &ICR5,
/*n, q*/ 5, q
};
return timer;
}
#endif
}
Timer timer = {
/*TCCRnQ*/ { nullptr, nullptr, nullptr },
/*OCRnQ*/ { nullptr, nullptr, nullptr },
/*ICRn*/ nullptr,
0, 0
};
return timer;
}
void set_pwm_frequency(const pin_t pin, int f_desired) {
Timer timer = get_pwm_timer(pin);
if (timer.n == 0) return; // Don't proceed if protected timer or not recognised
uint16_t size;
if (timer.n == 2) size = 255; else size = 65535;
uint16_t res = 255; // resolution (TOP value)
uint8_t j = 0; // prescaler index
uint8_t wgm = 1; // waveform generation mode
// Calculating the prescaler and resolution to use to achieve closest frequency
if (f_desired != 0) {
int f = (F_CPU) / (2 * 1024 * size) + 1; // Initialize frequency as lowest (non-zero) achievable
uint16_t prescaler[] = { 0, 1, 8, /*TIMER2 ONLY*/32, 64, /*TIMER2 ONLY*/128, 256, 1024 };
// loop over prescaler values
LOOP_S_L_N(i, 1, 8) {
uint16_t res_temp_fast = 255, res_temp_phase_correct = 255;
if (timer.n == 2) {
// No resolution calculation for TIMER2 unless enabled USE_OCR2A_AS_TOP
#if ENABLED(USE_OCR2A_AS_TOP)
const uint16_t rtf = (F_CPU) / (prescaler[i] * f_desired);
res_temp_fast = rtf - 1;
res_temp_phase_correct = rtf / 2;
#endif
}
else {
// Skip TIMER2 specific prescalers when not TIMER2
if (i == 3 || i == 5) continue;
const uint16_t rtf = (F_CPU) / (prescaler[i] * f_desired);
res_temp_fast = rtf - 1;
res_temp_phase_correct = rtf / 2;
}
LIMIT(res_temp_fast, 1U, size);
LIMIT(res_temp_phase_correct, 1U, size);
// Calculate frequencies of test prescaler and resolution values
const int f_temp_fast = (F_CPU) / (prescaler[i] * (1 + res_temp_fast)),
f_temp_phase_correct = (F_CPU) / (2 * prescaler[i] * res_temp_phase_correct),
f_diff = ABS(f - f_desired),
f_fast_diff = ABS(f_temp_fast - f_desired),
f_phase_diff = ABS(f_temp_phase_correct - f_desired);
// If FAST values are closest to desired f
if (f_fast_diff < f_diff && f_fast_diff <= f_phase_diff) {
// Remember this combination
f = f_temp_fast;
res = res_temp_fast;
j = i;
// Set the Wave Generation Mode to FAST PWM
if (timer.n == 2) {
wgm = (
#if ENABLED(USE_OCR2A_AS_TOP)
WGM2_FAST_PWM_OCR2A
#else
WGM2_FAST_PWM
#endif
);
}
else wgm = WGM_FAST_PWM_ICRn;
}
// If PHASE CORRECT values are closes to desired f
else if (f_phase_diff < f_diff) {
f = f_temp_phase_correct;
res = res_temp_phase_correct;
j = i;
// Set the Wave Generation Mode to PWM PHASE CORRECT
if (timer.n == 2) {
wgm = (
#if ENABLED(USE_OCR2A_AS_TOP)
WGM2_PWM_PC_OCR2A
#else
WGM2_PWM_PC
#endif
);
}
else wgm = WGM_PWM_PC_ICRn;
}
}
}
_SET_WGMnQ(timer.TCCRnQ, wgm);
_SET_CSn(timer.TCCRnQ, j);
if (timer.n == 2) {
#if ENABLED(USE_OCR2A_AS_TOP)
_SET_OCRnQ(timer.OCRnQ, 0, res); // Set OCR2A value (TOP) = res
#endif
}
else
_SET_ICRn(timer.ICRn, res); // Set ICRn value (TOP) = res
}
void set_pwm_duty(const pin_t pin, const uint16_t v, const uint16_t v_size/*=255*/, const bool invert/*=false*/) {
// If v is 0 or v_size (max), digitalWrite to LOW or HIGH.
// Note that digitalWrite also disables pwm output for us (sets COM bit to 0)
if (v == 0)
digitalWrite(pin, invert);
else if (v == v_size)
digitalWrite(pin, !invert);
else {
Timer timer = get_pwm_timer(pin);
if (timer.n == 0) return; // Don't proceed if protected timer or not recognised
// Set compare output mode to CLEAR -> SET or SET -> CLEAR (if inverted)
_SET_COMnQ(timer.TCCRnQ, (timer.q
#ifdef TCCR2
+ (timer.q == 2) // COM20 is on bit 4 of TCCR2, thus requires q + 1 in the macro
#endif
), COM_CLEAR_SET + invert
);
uint16_t top;
if (timer.n == 2) { // if TIMER2
top = (
#if ENABLED(USE_OCR2A_AS_TOP)
*timer.OCRnQ[0] // top = OCR2A
#else
255 // top = 0xFF (max)
#endif
);
}
else
top = *timer.ICRn; // top = ICRn
_SET_OCRnQ(timer.OCRnQ, timer.q, v * float(top) / float(v_size)); // Scale 8/16-bit v to top value
}
}
#endif // NEEDS_HARDWARE_PWM
#endif // __AVR__
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