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samd/machine_pwm: Add the machine.PWM class.

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Features are:
- 3 to 5 different frequency groups.
- Freq range of 1Hz - 24 MHz.
- Duty rate stays stable on freq change.

Keyword options to the PWM constructor:
- device=n Select a specific PWM device.  If no device is specified, a free
           device is chosen, if available at that pin.
- freq=nnnn
- duty_u16=nnnn
- duty_ns=nnnn
- invert=True/False Allowing two outputs on the same device/channel to have
                    complementary signals.

If both freq and duty are provided, PWM output will start immediately.

Pins at the same device have the same frequency.  If the PWM output number
exceeds the number of channels at the PWM device, the effctive channel_no
is output_no % channel_count.  So with a channel count of 4, output 7 is
assigned to channel 3.  Pins at a certain channel have the same frequency
and duty rate, but may be seperately inverted.
This commit is contained in:
robert-hh 2022-06-05 11:03:59 +02:00 committed by Damien George
parent 5c7e93ec48
commit d693758ab2
8 changed files with 376 additions and 0 deletions
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1
ports/samd/Makefile
View file

@ -142,6 +142,7 @@ SRC_QSTR += \
machine_adc.c \
machine_led.c \
machine_pin.c \
machine_pwm.c \
modutime.c \
modmachine.c \
modsamd.c \

362
ports/samd/machine_pwm.c Normal file
View file

@ -0,0 +1,362 @@
/*
* 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 "py/runtime.h"
#include "py/mphal.h"
#include "modmachine.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
} machine_pwm_obj_t;
#define PWM_NOT_INIT (0)
#define PWM_CLK_READY (1)
#define PWM_TCC_ENABLED (2)
#define PWM_MASTER_CLK (48000000)
#define PWM_FULL_SCALE (65536)
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 P%c%02u device=%u channel=%u output=%u",
"ABCD"[self->pin_id / 32], self->pin_id % 32, 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
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;
}
}
// 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 mp_obj_t mp_machine_pwm_freq_get(machine_pwm_obj_t *self) {
return MP_OBJ_NEW_SMALL_INT(PWM_MASTER_CLK / self->prescaler / self->period);
}
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) {
mp_raise_ValueError(MP_ERROR_TEXT("invalid freq"));
}
// 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"));
}
// 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->instance->CC[self->channel].reg * PWM_FULL_SCALE / (self->instance->PER.reg + 1));
}
STATIC void mp_machine_pwm_duty_set_u16(machine_pwm_obj_t *self, mp_int_t duty_u16) {
put_duty_value(self->device, self->channel, duty_u16);
// 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) {
self->instance->CCBUF[self->channel].reg = (uint64_t)duty_u16 * (self->instance->PER.reg + 1) / 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(1000000000ULL * self->instance->CC[self->channel].reg * self->prescaler / PWM_MASTER_CLK);
}
STATIC void mp_machine_pwm_duty_set_ns(machine_pwm_obj_t *self, mp_int_t duty_ns) {
put_duty_value(self->device, self->channel, duty_ns);
self->instance->CCBUF[self->channel].reg = (uint64_t)duty_ns * PWM_MASTER_CLK / self->prescaler / 1000000000ULL;
duty_type_flags[self->device] &= ~(1 << self->channel);
}

2
ports/samd/main.c
View file

@ -34,6 +34,7 @@
extern uint8_t _sstack, _estack, _sheap, _eheap;
extern void adc_deinit_all(void);
extern void pwm_deinit_all(void);
void samd_main(void) {
mp_stack_set_top(&_estack);
@ -64,6 +65,7 @@ void samd_main(void) {
mp_printf(MP_PYTHON_PRINTER, "MPY: soft reboot\n");
adc_deinit_all();
pwm_deinit_all();
gc_sweep_all();
mp_deinit();
}

1
ports/samd/modmachine.c
View file

@ -133,6 +133,7 @@ STATIC const mp_rom_map_elem_t machine_module_globals_table[] = {
{ MP_ROM_QSTR(MP_QSTR_ADC), MP_ROM_PTR(&machine_adc_type) },
{ MP_ROM_QSTR(MP_QSTR_LED), MP_ROM_PTR(&machine_led_type) },
{ MP_ROM_QSTR(MP_QSTR_Pin), MP_ROM_PTR(&machine_pin_type) },
{ MP_ROM_QSTR(MP_QSTR_PWM), MP_ROM_PTR(&machine_pwm_type) },
{ MP_ROM_QSTR(MP_QSTR_SoftI2C), MP_ROM_PTR(&mp_machine_soft_i2c_type) },
{ MP_ROM_QSTR(MP_QSTR_SoftSPI), MP_ROM_PTR(&mp_machine_soft_spi_type) },
};

1
ports/samd/modmachine.h
View file

@ -31,5 +31,6 @@
extern const mp_obj_type_t machine_adc_type;
extern const mp_obj_type_t machine_led_type;
extern const mp_obj_type_t machine_pin_type;
extern const mp_obj_type_t machine_pwm_type;
#endif // MICROPY_INCLUDED_SAMD_MODMACHINE_H

4
ports/samd/mpconfigport.h
View file

@ -99,6 +99,10 @@
#define MICROPY_PY_UASYNCIO (1)
#define MICROPY_PY_MACHINE_SOFTI2C (1)
#define MICROPY_PY_MACHINE_SOFTSPI (1)
#define MICROPY_PY_MACHINE_PWM (1)
#define MICROPY_PY_MACHINE_PWM_INIT (0)
#define MICROPY_PY_MACHINE_PWM_DUTY_U16_NS (1)
#define MICROPY_PY_MACHINE_PWM_INCLUDEFILE "ports/samd/machine_pwm.c"
#define MP_STATE_PORT MP_STATE_VM

4
ports/samd/mphalport.c
View file

@ -61,6 +61,10 @@ void mp_hal_set_pin_mux(mp_hal_pin_obj_t pin, uint8_t mux) {
}
}
void mp_hal_clr_pin_mux(mp_hal_pin_obj_t pin) {
int pin_grp = pin / 32;
PORT->Group[pin_grp].PINCFG[pin % 32].bit.PMUXEN = 0; // Disable Mux
}
void mp_hal_delay_ms(mp_uint_t ms) {
if (ms > 10) {

1
ports/samd/mphalport.h
View file

@ -84,6 +84,7 @@ extern uint32_t machine_pin_open_drain_mask[];
mp_hal_pin_obj_t mp_hal_get_pin_obj(mp_obj_t pin_in);
void mp_hal_set_pin_mux(mp_hal_pin_obj_t pin, uint8_t mux);
void mp_hal_clr_pin_mux(mp_hal_pin_obj_t pin);
static inline unsigned int mp_hal_pin_name(mp_hal_pin_obj_t pin) {
return pin;