circuitpython/ports/atmel-samd/common-hal/pulseio/PulseOut.c

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/*
* This file is part of the MicroPython 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 "common-hal/pulseio/PulseOut.h"
#include <stdint.h>
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#include "hal/include/hal_gpio.h"
#include "mpconfigport.h"
#include "samd/pins.h"
#include "samd/timers.h"
#include "py/gc.h"
#include "py/runtime.h"
#include "shared-bindings/pulseio/PulseOut.h"
// This timer is shared amongst all PulseOut objects under the assumption that
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// the code is single threaded.
static uint8_t refcount = 0;
static uint8_t pulseout_tc_index = 0xff;
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static __IO PORT_PINCFG_Type *active_pincfg = NULL;
static uint16_t *pulse_buffer = NULL;
static volatile uint16_t pulse_index = 0;
static uint16_t pulse_length;
static volatile uint32_t current_compare = 0;
static void turn_on(__IO PORT_PINCFG_Type * pincfg) {
pincfg->reg = PORT_PINCFG_PMUXEN;
}
static void turn_off(__IO PORT_PINCFG_Type * pincfg) {
pincfg->reg = PORT_PINCFG_RESETVALUE;
}
void pulse_finish(void) {
pulse_index++;
if (active_pincfg == NULL) {
return;
}
// Always turn it off.
turn_off(active_pincfg);
if (pulse_index >= pulse_length) {
return;
}
current_compare = (current_compare + pulse_buffer[pulse_index] * 3 / 4) & 0xffff;
Tc* tc = tc_insts[pulseout_tc_index];
tc->COUNT16.CC[0].reg = current_compare;
if (pulse_index % 2 == 0) {
turn_on(active_pincfg);
}
}
void pulseout_interrupt_handler(uint8_t index) {
if (index != pulseout_tc_index) return;
Tc* tc = tc_insts[index];
if (!tc->COUNT16.INTFLAG.bit.MC0) return;
pulse_finish();
// Clear the interrupt bit.
tc->COUNT16.INTFLAG.reg = TC_INTFLAG_MC0;
}
void pulseout_reset() {
refcount = 0;
pulseout_tc_index = 0xff;
active_pincfg = NULL;
}
void common_hal_pulseio_pulseout_construct(pulseio_pulseout_obj_t* self,
const pulseio_pwmout_obj_t* carrier) {
if (refcount == 0) {
// Find a spare timer.
Tc *tc = NULL;
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int8_t index = TC_INST_NUM - 1;
for (; index >= 0; index--) {
if (tc_insts[index]->COUNT16.CTRLA.bit.ENABLE == 0) {
tc = tc_insts[index];
break;
}
}
if (tc == NULL) {
mp_raise_RuntimeError("All timers in use");
}
pulseout_tc_index = index;
// We use GCLK0 for SAMD21 and GCLK1 for SAMD51 because they both run at 48mhz making our
// math the same across the boards.
#ifdef SAMD21
turn_on_clocks(true, index, 0);
#endif
#ifdef SAMD51
turn_on_clocks(true, index, 1);
#endif
#ifdef SAMD21
tc->COUNT16.CTRLA.reg = TC_CTRLA_MODE_COUNT16 |
TC_CTRLA_PRESCALER_DIV64 |
TC_CTRLA_WAVEGEN_NFRQ;
#endif
#ifdef SAMD51
tc_reset(tc);
tc_set_enable(tc, false);
tc->COUNT16.CTRLA.reg = TC_CTRLA_MODE_COUNT16 | TC_CTRLA_PRESCALER_DIV64;
tc->COUNT16.WAVE.reg = TC_WAVE_WAVEGEN_NFRQ;
#endif
tc_set_enable(tc, true);
tc->COUNT16.CTRLBSET.reg = TC_CTRLBSET_CMD_STOP;
}
refcount++;
self->pin = carrier->pin->pin;
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PortGroup *const port_base = &PORT->Group[GPIO_PORT(self->pin)];
self->pincfg = &port_base->PINCFG[self->pin % 32];
// Set the port to output a zero.
port_base->OUTCLR.reg = 1 << (self->pin % 32);
port_base->DIRSET.reg = 1 << (self->pin % 32);
// Turn off the pinmux which should connect the port output.
turn_off(self->pincfg);
}
bool common_hal_pulseio_pulseout_deinited(pulseio_pulseout_obj_t* self) {
return self->pin == NO_PIN;
}
void common_hal_pulseio_pulseout_deinit(pulseio_pulseout_obj_t* self) {
if (common_hal_pulseio_pulseout_deinited(self)) {
return;
}
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PortGroup *const port_base = &PORT->Group[GPIO_PORT(self->pin)];
port_base->DIRCLR.reg = 1 << (self->pin % 32);
turn_on(self->pincfg);
refcount--;
if (refcount == 0) {
tc_reset(tc_insts[pulseout_tc_index]);
pulseout_tc_index = 0xff;
}
self->pin = NO_PIN;
}
void common_hal_pulseio_pulseout_send(pulseio_pulseout_obj_t* self, uint16_t* pulses, uint16_t length) {
if (active_pincfg != NULL) {
mp_raise_RuntimeError("Another send is already active");
}
active_pincfg = self->pincfg;
pulse_buffer = pulses;
pulse_index = 0;
pulse_length = length;
current_compare = pulses[0] * 3 / 4;
Tc* tc = tc_insts[pulseout_tc_index];
tc->COUNT16.CC[0].reg = current_compare;
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// Clear our interrupt in case it was set earlier
tc->COUNT16.INTFLAG.reg = TC_INTFLAG_MC0;
tc->COUNT16.INTENSET.reg = TC_INTENSET_MC0;
tc_enable_interrupts(pulseout_tc_index);
turn_on(active_pincfg);
tc->COUNT16.CTRLBSET.reg = TC_CTRLBSET_CMD_RETRIGGER;
while(pulse_index < length) {
// Do other things while we wait. The interrupts will handle sending the
// signal.
#ifdef MICROPY_VM_HOOK_LOOP
MICROPY_VM_HOOK_LOOP
#endif
}
tc->COUNT16.CTRLBSET.reg = TC_CTRLBSET_CMD_STOP;
tc->COUNT16.INTENCLR.reg = TC_INTENCLR_MC0;
tc_disable_interrupts(pulseout_tc_index);
active_pincfg = NULL;
}