circuitpython/atmel-samd/common-hal/pulseio/PWMOut.c

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/*
* This file is part of the Micro Python project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2016 Damien P. George
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <stdint.h>
#include "py/runtime.h"
#include "common-hal/pulseio/PWMOut.h"
#include "shared-bindings/pulseio/PWMOut.h"
#include "samd21_pins.h"
#undef ENABLE
uint32_t target_timer_frequencies[TC_INST_NUM + TCC_INST_NUM];
uint8_t timer_refcount[TC_INST_NUM + TCC_INST_NUM];
const uint16_t prescaler[8] = {1, 2, 4, 8, 16, 64, 256, 1024};
// This bitmask keeps track of which channels of a TCC are currently claimed.
uint8_t tcc_channels[3] = {0xf0, 0xfc, 0xfc};
void pwmout_reset(void) {
// Reset all but TC5
for (int i = 0; i < TC_INST_NUM + TCC_INST_NUM; i++) {
if (i == 5) {
target_timer_frequencies[i] = 1000;
timer_refcount[i] = 1;
} else {
target_timer_frequencies[i] = 0;
timer_refcount[i] = 0;
}
}
Tcc *tccs[TCC_INST_NUM] = TCC_INSTS;
for (int i = 0; i < TCC_INST_NUM; i++) {
tccs[i]->CTRLA.bit.SWRST = 1;
}
Tc *tcs[TC_INST_NUM] = TC_INSTS;
for (int i = 0; i < TC_INST_NUM; i++) {
if (tcs[i] == TC5) {
continue;
}
tcs[i]->COUNT16.CTRLA.bit.SWRST = 1;
}
}
bool channel_ok(const pin_timer_t* t, uint8_t index) {
return (!t->is_tc && (tcc_channels[index] & (1 << t->channel)) == 0) ||
t->is_tc;
}
void common_hal_pulseio_pwmout_construct(pulseio_pwmout_obj_t* self,
const mcu_pin_obj_t* pin,
uint16_t duty,
uint32_t frequency,
bool variable_frequency) {
self->pin = pin;
self->variable_frequency = variable_frequency;
if (pin->primary_timer.tc == 0 && pin->secondary_timer.tc == 0) {
mp_raise_ValueError("Invalid pin");
}
if (frequency == 0 || frequency > 6000000) {
mp_raise_ValueError("Invalid PWM frequency");
}
uint16_t primary_timer_index = 0xff;
uint16_t secondary_timer_index = 0xff;
if (pin->primary_timer.tc != NULL) {
primary_timer_index = (((uint32_t) pin->primary_timer.tcc) - ((uint32_t) TCC0)) / 0x400;
}
if (pin->secondary_timer.tc != NULL) {
secondary_timer_index = (((uint32_t) pin->secondary_timer.tcc) - ((uint32_t) TCC0)) / 0x400;
}
// Figure out which timer we are using.
// First see if a timer is already going with the frequency we want and our
// channel is unused.
// NOTE(shawcroft): The enable bit is in the same position for TC and TCC so
// we treat them all as TCC for checking ENABLE.
const pin_timer_t* t = NULL;
uint8_t index = 0;
if (!variable_frequency &&
primary_timer_index != 0xff &&
target_timer_frequencies[primary_timer_index] == frequency &&
pin->primary_timer.tcc->CTRLA.bit.ENABLE == 1 &&
channel_ok(&pin->primary_timer, primary_timer_index)) {
t = &pin->primary_timer;
index = primary_timer_index;
} else if (!variable_frequency &&
secondary_timer_index != 0xff &&
target_timer_frequencies[secondary_timer_index] == frequency &&
pin->secondary_timer.tcc->CTRLA.bit.ENABLE == 1 &&
channel_ok(&pin->secondary_timer, secondary_timer_index)) {
t = &pin->secondary_timer;
index = secondary_timer_index;
} else {
// Pick an unused timer if available.
// Check the secondary timer first since its always a nicer TCC (when it
// exists)
if (pin->secondary_timer.tc != 0 &&
timer_refcount[secondary_timer_index] == 0 &&
pin->secondary_timer.tcc->CTRLA.bit.ENABLE == 0) {
t = &pin->secondary_timer;
index = secondary_timer_index;
} else if (pin->primary_timer.tc != 0 &&
(!pin->primary_timer.is_tc || pin->primary_timer.channel == 1) &&
timer_refcount[primary_timer_index] == 0) {
t = &pin->primary_timer;
index = primary_timer_index;
}
if (t == NULL) {
mp_raise_RuntimeError("All timers in use");
return;
}
uint8_t resolution = 0;
if (t->is_tc) {
resolution = 16;
} else {
resolution = 24;
}
// First determine the divisor that gets us the highest resolution.
uint32_t system_clock = system_cpu_clock_get_hz();
uint32_t top;
uint8_t divisor;
for (divisor = 0; divisor < 8; divisor++) {
top = (system_clock / prescaler[divisor] / frequency) - 1;
if (top < (1u << resolution)) {
break;
}
}
if (t->is_tc) {
struct tc_config config_tc;
tc_get_config_defaults(&config_tc);
config_tc.counter_size = TC_COUNTER_SIZE_16BIT;
config_tc.clock_prescaler = TC_CTRLA_PRESCALER(divisor);
config_tc.wave_generation = TC_WAVE_GENERATION_MATCH_PWM;
config_tc.counter_16_bit.compare_capture_channel[0] = top;
tc_init(&self->tc_instance, t->tc, &config_tc);
tc_enable(&self->tc_instance);
} else {
struct tcc_config config_tcc;
tcc_get_config_defaults(&config_tcc, t->tcc);
config_tcc.counter.clock_prescaler = divisor;
config_tcc.counter.period = top;
config_tcc.compare.wave_generation = TCC_WAVE_GENERATION_SINGLE_SLOPE_PWM;
tcc_init(&self->tcc_instance, t->tcc, &config_tcc);
tcc_enable(&self->tcc_instance);
}
target_timer_frequencies[index] = frequency;
timer_refcount[index]++;
}
if (!t->is_tc) {
if (variable_frequency) {
// We're changing frequency so claim all of the channels.
tcc_channels[index] = 0xff;
} else {
tcc_channels[index] |= (1 << t->channel);
}
}
self->timer = t;
// Connect the wave output to the outside world.
struct system_pinmux_config pin_config;
system_pinmux_get_config_defaults(&pin_config);
pin_config.mux_position = &self->pin->primary_timer == t ? MUX_E : MUX_F;
pin_config.direction = SYSTEM_PINMUX_PIN_DIR_OUTPUT;
system_pinmux_pin_set_config(pin->pin, &pin_config);
common_hal_pulseio_pwmout_set_duty_cycle(self, duty);
}
extern void common_hal_pulseio_pwmout_deinit(pulseio_pwmout_obj_t* self) {
const pin_timer_t* t = self->timer;
uint8_t index = (((uint32_t) t->tcc) - ((uint32_t) TCC0)) / 0x400;
timer_refcount[index]--;
if (!t->is_tc) {
tcc_channels[index] &= ~(1 << t->channel);
}
if (timer_refcount[index] == 0) {
target_timer_frequencies[index] = 0;
if (t->is_tc) {
tc_disable(&self->tc_instance);
} else {
if (t->tcc == TCC0) {
tcc_channels[index] = 0xf0;
} else {
tcc_channels[index] = 0xfc;
}
tcc_disable(&self->tcc_instance);
tcc_reset(&self->tcc_instance);
}
}
reset_pin(self->pin->pin);
}
extern void common_hal_pulseio_pwmout_set_duty_cycle(pulseio_pwmout_obj_t* self, uint16_t duty) {
const pin_timer_t* t = self->timer;
if (t->is_tc) {
uint32_t top = ((uint32_t) t->tc->COUNT16.CC[0].reg + 1);
uint16_t adjusted_duty = top * duty / 0xffff;
tc_set_compare_value(&self->tc_instance, t->channel, adjusted_duty);
} else {
uint32_t top = t->tcc->PER.reg + 1;
uint32_t adjusted_duty = ((uint64_t) top) * duty / 0xffff;
tcc_set_compare_value(&self->tcc_instance, t->channel, adjusted_duty);
}
}
uint16_t common_hal_pulseio_pwmout_get_duty_cycle(pulseio_pwmout_obj_t* self) {
const pin_timer_t* t = self->timer;
if (t->is_tc) {
uint16_t top = t->tc->COUNT16.CC[0].reg;
while (tc_is_syncing(&self->tc_instance)) {
/* Wait for sync */
}
uint16_t cv = t->tc->COUNT16.CC[t->channel].reg;
return cv * 0xffff / top;
} else {
uint32_t top = t->tcc->PER.reg;
uint32_t cv = 0;
if ((t->tcc->STATUS.vec.CCBV & (1 << t->channel)) != 0) {
cv = t->tcc->CCB[t->channel].reg;
} else {
cv = t->tcc->CC[t->channel].reg;
}
return cv * 0xffff / top;
}
}
void common_hal_pulseio_pwmout_set_frequency(pulseio_pwmout_obj_t* self,
uint32_t frequency) {
if (frequency == 0 || frequency > 6000000) {
mp_raise_ValueError("Invalid PWM frequency");
}
const pin_timer_t* t = self->timer;
uint8_t resolution;
if (t->is_tc) {
resolution = 16;
} else {
resolution = 24;
}
uint32_t system_clock = system_cpu_clock_get_hz();
uint32_t new_top;
uint8_t new_divisor;
for (new_divisor = 0; new_divisor < 8; new_divisor++) {
new_top = (system_clock / prescaler[new_divisor] / frequency) - 1;
if (new_top < (1u << resolution)) {
break;
}
}
uint16_t old_duty = common_hal_pulseio_pwmout_get_duty_cycle(self);
uint8_t old_divisor;
if (t->is_tc) {
old_divisor = t->tc->COUNT16.CTRLA.bit.PRESCALER;
} else {
old_divisor = t->tcc->CTRLA.bit.PRESCALER;
}
if (new_divisor != old_divisor) {
if (t->is_tc) {
tc_disable(&self->tc_instance);
t->tc->COUNT16.CTRLA.bit.PRESCALER = new_divisor;
tc_enable(&self->tc_instance);
} else {
tcc_disable(&self->tcc_instance);
t->tcc->CTRLA.bit.PRESCALER = new_divisor;
tcc_enable(&self->tcc_instance);
}
}
if (t->is_tc) {
while (tc_is_syncing(&self->tc_instance)) {
/* Wait for sync */
}
t->tc->COUNT16.CC[0].reg = new_top;
} else {
tcc_set_top_value(&self->tcc_instance, new_top);
}
common_hal_pulseio_pwmout_set_duty_cycle(self, old_duty);
}
uint32_t common_hal_pulseio_pwmout_get_frequency(pulseio_pwmout_obj_t* self) {
uint32_t system_clock = system_cpu_clock_get_hz();
const pin_timer_t* t = self->timer;
uint32_t top;
uint8_t divisor;
if (t->is_tc) {
top = t->tc->COUNT16.CC[0].reg;
divisor = t->tc->COUNT16.CTRLA.bit.PRESCALER;
} else {
top = t->tcc->PER.reg;
divisor = t->tcc->CTRLA.bit.PRESCALER;
}
return (system_clock / prescaler[divisor]) / (top + 1);
}
bool common_hal_pulseio_pwmout_get_variable_frequency(pulseio_pwmout_obj_t* self) {
return self->variable_frequency;
}