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circuitpython/ports/samd/machine_pwm.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2020-2021 Damien P. George
* Copyright (c) 2022 Robert Hammelrath
*
* 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 <string.h>
#include "py/runtime.h"
#include "py/mphal.h"
#include "modmachine.h"
#include "clock_config.h"
#include "sam.h"
#include "pin_af.h"
/******************************************************************************/
// MicroPython bindings for machine.PWM
typedef struct _machine_pwm_obj_t {
mp_obj_base_t base;
Tcc *instance;
uint8_t pin_id;
uint8_t alt_fct;
uint8_t device;
uint8_t channel;
uint8_t output;
uint16_t prescaler;
uint32_t period; // full period count ticks
uint32_t duty_ns; // just for reporting
uint16_t duty_u16; // just for reporting
} machine_pwm_obj_t;
#define PWM_NOT_INIT (0)
#define PWM_CLK_READY (1)
#define PWM_TCC_ENABLED (2)
#define PWM_MASTER_CLK (get_peripheral_freq())
#define PWM_FULL_SCALE (65536)
#define PWM_UPDATE_TIMEOUT (2000)
static Tcc *tcc_instance[] = TCC_INSTS;
#if defined(MCU_SAMD21)
static const int tcc_gclk_id[] = {
GCLK_CLKCTRL_ID_TCC0_TCC1, GCLK_CLKCTRL_ID_TCC0_TCC1, GCLK_CLKCTRL_ID_TCC2_TC3
};
const uint8_t tcc_channel_count[] = {4, 2, 2};
const static uint8_t tcc_channel_offset[] = {0, 4, 6};
static uint32_t pwm_duty_values[8];
#define PERBUF PERB
#define CCBUF CCB
#elif defined(MCU_SAMD51)
static const int tcc_gclk_id[] = {
TCC0_GCLK_ID, TCC1_GCLK_ID, TCC2_GCLK_ID,
#if TCC_INST_NUM > 3
TCC3_GCLK_ID, TCC4_GCLK_ID
#endif
};
#if TCC_INST_NUM > 3
const uint8_t tcc_channel_count[] = {6, 4, 3, 2, 2};
const static uint8_t tcc_channel_offset[] = {0, 6, 10, 13, 15};
static uint32_t pwm_duty_values[17];
#else
const uint8_t tcc_channel_count[] = {6, 4, 3};
const static uint8_t tcc_channel_offset[] = {0, 6, 10};
static uint32_t pwm_duty_values[13];
#endif // TCC_INST_NUM > 3
#endif // defined(MCU_SAMD51)
#define put_duty_value(device, channel, duty) \
pwm_duty_values[tcc_channel_offset[device] + channel] = duty;
#define get_duty_value(device, channel) \
pwm_duty_values[tcc_channel_offset[device] + channel]
static uint8_t duty_type_flags[TCC_INST_NUM];
static uint8_t device_status[TCC_INST_NUM];
static uint8_t output_active[TCC_INST_NUM];
const uint16_t prescaler_table[] = {1, 2, 4, 8, 16, 64, 256, 1024};
STATIC void pwm_stop_device(int device);
STATIC void mp_machine_pwm_freq_set(machine_pwm_obj_t *self, mp_int_t freq);
STATIC void mp_machine_pwm_duty_set_u16(machine_pwm_obj_t *self, mp_int_t duty_u16);
STATIC void mp_machine_pwm_duty_set_ns(machine_pwm_obj_t *self, mp_int_t duty_ns);
STATIC void mp_machine_pwm_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
machine_pwm_obj_t *self = MP_OBJ_TO_PTR(self_in);
mp_printf(print, "PWM(%s, device=%u, channel=%u, output=%u)",
pin_name(self->pin_id), self->device, self->channel, self->output);
}
// PWM(pin)
STATIC mp_obj_t mp_machine_pwm_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
enum { ARG_pin, ARG_freq, ARG_duty_u16, ARG_duty_ns, ARG_invert, ARG_device };
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_pin, MP_ARG_REQUIRED | MP_ARG_OBJ },
{ MP_QSTR_freq, MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_duty_u16, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_duty_ns, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_invert, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_device, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
};
// Parse the arguments.
mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
mp_arg_parse_all_kw_array(n_args, n_kw, all_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
// Get GPIO and optional device to connect to PWM.
uint32_t pin_id = mp_hal_get_pin_obj(args[ARG_pin].u_obj);
int32_t wanted_dev = args[ARG_device].u_int; // -1 = any
// Get the peripheral object and populate it
pwm_config_t config = get_pwm_config(pin_id, wanted_dev, device_status);
uint8_t device = config.device_channel >> 4;
if (device >= TCC_INST_NUM) {
mp_raise_ValueError(MP_ERROR_TEXT("wrong device"));
}
machine_pwm_obj_t *self = mp_obj_malloc(machine_pwm_obj_t, &machine_pwm_type);
self->instance = tcc_instance[device];
self->device = device;
self->pin_id = pin_id;
self->alt_fct = config.alt_fct;
self->channel = (config.device_channel & 0x0f) % tcc_channel_count[device];
self->output = config.device_channel & 0x0f;
self->prescaler = 1;
self->period = 1; // Use an invalid but safe value
self->duty_u16 = self->duty_ns = 0;
put_duty_value(self->device, self->channel, 0);
Tcc *tcc = self->instance;
if (device_status[device] == PWM_NOT_INIT) {
// Enable the device clock at first use.
#if defined(MCU_SAMD21)
// Enable synchronous clock. The bits are nicely arranged
PM->APBCMASK.reg |= PM_APBCMASK_TCC0 << device;
// Select multiplexer generic clock source and enable.
GCLK->CLKCTRL.reg = GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK2 | tcc_gclk_id[device];
// Wait while it updates synchronously.
while (GCLK->STATUS.bit.SYNCBUSY) {
}
#elif defined(MCU_SAMD51)
// GenClk2 to the tcc
GCLK->PCHCTRL[tcc_gclk_id[device]].reg = GCLK_PCHCTRL_CHEN | GCLK_PCHCTRL_GEN(2);
while (GCLK->SYNCBUSY.reg & GCLK_SYNCBUSY_GENCTRL_GCLK2) {
}
// Enable MCLK
switch (device) {
case 0:
MCLK->APBBMASK.reg |= MCLK_APBBMASK_TCC0;
break;
case 1:
MCLK->APBBMASK.reg |= MCLK_APBBMASK_TCC1;
break;
case 2:
MCLK->APBCMASK.reg |= MCLK_APBCMASK_TCC2;
break;
#if TCC_INST_NUM > 3
case 3:
MCLK->APBCMASK.reg |= MCLK_APBCMASK_TCC3;
break;
case 4:
MCLK->APBDMASK.reg |= MCLK_APBDMASK_TCC4;
break;
#endif
}
#endif
// Reset the device
tcc->CTRLA.reg = TCC_CTRLA_SWRST;
while (tcc->SYNCBUSY.reg & TCC_SYNCBUSY_SWRST) {
}
tcc->CTRLA.reg = TCC_CTRLA_PRESCALER_DIV1;
tcc->WAVE.reg = TCC_WAVE_WAVEGEN_NPWM;
// Flag the clock as initialized, but not the device as enabled.
device_status[device] = PWM_CLK_READY;
}
if (args[ARG_invert].u_int != -1) {
bool invert = !!args[ARG_invert].u_int;
if (device_status[device] != PWM_CLK_READY) {
pwm_stop_device(device);
}
uint32_t mask = 1 << (self->output + TCC_DRVCTRL_INVEN0_Pos);
if (invert) {
tcc->DRVCTRL.reg |= mask;
} else {
tcc->DRVCTRL.reg &= ~(mask);
}
}
if (args[ARG_duty_u16].u_int != -1) {
mp_machine_pwm_duty_set_u16(self, args[ARG_duty_u16].u_int);
}
if (args[ARG_duty_ns].u_int != -1) {
mp_machine_pwm_duty_set_ns(self, args[ARG_duty_ns].u_int);
}
if (args[ARG_freq].u_int != -1) {
mp_machine_pwm_freq_set(self, args[ARG_freq].u_int);
}
return MP_OBJ_FROM_PTR(self);
}
STATIC void pwm_stop_device(int device) {
Tcc *tcc = tcc_instance[device];
tcc->CTRLA.bit.ENABLE = 0;
while (tcc->SYNCBUSY.reg & TCC_SYNCBUSY_ENABLE) {
}
device_status[device] = PWM_CLK_READY;
}
// Stop all TTC devices
void pwm_deinit_all(void) {
for (int i = 0; i < TCC_INST_NUM; i++) {
Tcc *tcc = tcc_instance[i];
tcc->CTRLA.reg = TCC_CTRLA_SWRST;
while (tcc->SYNCBUSY.reg & TCC_SYNCBUSY_SWRST) {
}
device_status[i] = PWM_NOT_INIT;
duty_type_flags[i] = 0;
output_active[i] = 0;
memset(pwm_duty_values, 0, sizeof(pwm_duty_values));
}
}
// Switch off an output. If all outputs of a device are off,
// switch off that device.
// This stops all channels, but keeps the configuration
// Calling pwm.freq(n) will start an instance again.
STATIC void mp_machine_pwm_deinit(machine_pwm_obj_t *self) {
mp_hal_clr_pin_mux(self->pin_id); // Switch the output off
output_active[self->device] &= ~(1 << self->output); // clear output flasg
// Stop the device, if no output is active.
if (output_active[self->device] == 0) {
pwm_stop_device(self->device);
}
}
STATIC void wait_for_register_update(Tcc *tcc) {
// Wait for a period's end (may be long) to have the change settled
// Each loop cycle takes at least 1 ms, giving an implicit timeout.
for (int i = 0; i < PWM_UPDATE_TIMEOUT; i++) {
if (tcc->INTFLAG.reg & TCC_INTFLAG_OVF) {
break;
}
MICROPY_EVENT_POLL_HOOK
}
// Clear the flag, telling that a cycle has been handled.
tcc->INTFLAG.reg = TCC_INTFLAG_OVF;
}
STATIC mp_obj_t mp_machine_pwm_freq_get(machine_pwm_obj_t *self) {
if (self->instance->CTRLA.reg & TCC_CTRLA_ENABLE) {
return MP_OBJ_NEW_SMALL_INT(PWM_MASTER_CLK / self->prescaler / self->period);
} else {
return MP_OBJ_NEW_SMALL_INT(0);
}
}
STATIC void mp_machine_pwm_freq_set(machine_pwm_obj_t *self, mp_int_t freq) {
// Set the frequency. The period counter is 24 bit or 16 bit with a pre-scaling
// of up to 1024, allowing a range from 24 MHz down to 1 Hz.
static const uint32_t max_period[5] = {1 << 24, 1 << 24, 1 << 16, 1 << 16, 1 << 16};
Tcc *tcc = self->instance;
if (freq < 1) {
pwm_stop_device(self->device);
return;
}
// Get the actual settings of prescaler & period from the unit
// To be able for cope for changes.
uint32_t prev_period = tcc->PER.reg + 1;
// Check for the right prescaler
uint8_t index;
for (index = 0; index < 8; index++) {
uint32_t temp = PWM_MASTER_CLK / prescaler_table[index] / freq;
if (temp < max_period[self->device]) {
break;
}
}
self->prescaler = prescaler_table[index];
uint32_t period = PWM_MASTER_CLK / self->prescaler / freq;
if (period < 2) {
mp_raise_ValueError(MP_ERROR_TEXT("freq too large"));
}
// If the PWM is running, ensure that a cycle has passed since the
// previous setting before setting a new frequency/duty value
if (tcc->CTRLA.reg & TCC_CTRLA_ENABLE) {
wait_for_register_update(tcc);
}
// Check, if the prescaler has to be changed and stop the device if so.
if (index != tcc->CTRLA.bit.PRESCALER) {
// stop the device
pwm_stop_device(self->device);
// update the prescaler
tcc->CTRLA.bit.PRESCALER = index;
}
// Lock the update to get a glitch-free change of period and duty cycle
tcc->CTRLBSET.reg = TCC_CTRLBSET_LUPD;
tcc->PERBUF.reg = period - 1;
self->period = period;
// Check if the Duty rate has to be aligned again when freq or prescaler were changed.
// This condition is as well true on first call after instantiation. So (re-)configure
// all channels with a duty_u16 setting.
if (period != prev_period) {
for (uint16_t ch = 0; ch < tcc_channel_count[self->device]; ch++) {
if ((duty_type_flags[self->device] & (1 << ch)) != 0) { // duty_u16 type?
tcc->CCBUF[ch].reg = (uint64_t)get_duty_value(self->device, ch) * period /
PWM_FULL_SCALE;
}
}
}
// If the prescaler was changed, the device is disabled. So this condition is true
// after the instantiation and after a prescaler change.
// (re-)configure all channels with a duty_ns setting.
if (!(tcc->CTRLA.reg & TCC_CTRLA_ENABLE)) {
for (uint16_t ch = 0; ch < tcc_channel_count[self->device]; ch++) {
if ((duty_type_flags[self->device] & (1 << ch)) == 0) { // duty_ns type?
tcc->CCBUF[ch].reg = (uint64_t)get_duty_value(self->device, ch) * PWM_MASTER_CLK /
self->prescaler / 1000000000ULL;
}
}
}
// Remember the output as active.
output_active[self->device] |= 1 << self->output; // set output flag
// (Re-)Select PWM function for given GPIO.
mp_hal_set_pin_mux(self->pin_id, self->alt_fct);
// Enable the device, if required.
if ((device_status[self->device] & PWM_TCC_ENABLED) == 0) {
tcc->CTRLBSET.reg = TCC_CTRLBSET_CMD_UPDATE;
tcc->CTRLA.reg |= TCC_CTRLA_ENABLE;
while (tcc->SYNCBUSY.reg & TCC_SYNCBUSY_ENABLE) {
}
device_status[self->device] |= PWM_TCC_ENABLED;
}
// Unlock the register update, now that the settings are complete
tcc->CTRLBCLR.reg = TCC_CTRLBCLR_LUPD;
}
STATIC mp_obj_t mp_machine_pwm_duty_get_u16(machine_pwm_obj_t *self) {
return MP_OBJ_NEW_SMALL_INT(self->duty_u16);
}
STATIC void mp_machine_pwm_duty_set_u16(machine_pwm_obj_t *self, mp_int_t duty_u16) {
// Remember the values for update & reporting
put_duty_value(self->device, self->channel, duty_u16);
self->duty_u16 = duty_u16;
self->duty_ns = 0;
// If the device is enabled, than the period is set and we get a reasonable value for
// the duty cycle, set to the CCBUF register. Otherwise, PWM does not start.
if (self->instance->CTRLA.reg & TCC_CTRLA_ENABLE) {
// Ensure that a cycle has passed updating the registers
// since the previous setting before setting a new duty value
wait_for_register_update(self->instance);
self->instance->CCBUF[self->channel].reg = (uint64_t)duty_u16 * (self->period) / PWM_FULL_SCALE;
}
duty_type_flags[self->device] |= 1 << self->channel;
}
STATIC mp_obj_t mp_machine_pwm_duty_get_ns(machine_pwm_obj_t *self) {
return MP_OBJ_NEW_SMALL_INT(self->duty_ns);
}
STATIC void mp_machine_pwm_duty_set_ns(machine_pwm_obj_t *self, mp_int_t duty_ns) {
// Remember the values for update & reporting
put_duty_value(self->device, self->channel, duty_ns);
self->duty_ns = duty_ns;
self->duty_u16 = 0;
// Ensure that a cycle has passed updating the registers
// since the previous setting before setting a new duty value
wait_for_register_update(self->instance);
self->instance->CCBUF[self->channel].reg = (uint64_t)duty_ns * PWM_MASTER_CLK / self->prescaler / 1000000000ULL;
duty_type_flags[self->device] &= ~(1 << self->channel);
}
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