circuitpython/ports/nrf/drivers/ticker.c

171 lines
5.1 KiB
C

/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2016 Mark Shannon
*
* 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/mphal.h"
#if MICROPY_PY_MACHINE_SOFT_PWM
#include "ticker.h"
#include "nrfx_glue.h"
#define FastTicker NRF_TIMER1
#define FastTicker_IRQn TIMER1_IRQn
#define FastTicker_IRQHandler TIMER1_IRQHandler
#define SlowTicker_IRQn SWI0_IRQn
#define SlowTicker_IRQHandler SWI0_IRQHandler
// Ticker callback function called every MACRO_TICK
static volatile uint8_t m_num_of_slow_tickers = 0;
static volatile callback_ptr m_slow_tickers[2] = {NULL, NULL};
void ticker_init0(void) {
NRF_TIMER_Type *ticker = FastTicker;
#ifdef NRF51
ticker->POWER = 1;
#endif
__NOP();
ticker_stop();
ticker->TASKS_CLEAR = 1;
ticker->CC[3] = MICROSECONDS_PER_MACRO_TICK;
ticker->MODE = TIMER_MODE_MODE_Timer;
ticker->BITMODE = TIMER_BITMODE_BITMODE_24Bit << TIMER_BITMODE_BITMODE_Pos;
ticker->PRESCALER = 4; // 1 tick == 1 microsecond
ticker->INTENSET = TIMER_INTENSET_COMPARE3_Msk;
ticker->SHORTS = 0;
#ifdef NRF51
NRFX_IRQ_PRIORITY_SET(FastTicker_IRQn, 1);
#else
NRFX_IRQ_PRIORITY_SET(FastTicker_IRQn, 2);
#endif
NRFX_IRQ_PRIORITY_SET(SlowTicker_IRQn, 3);
NRFX_IRQ_PRIORITY_SET(SlowTicker_IRQn, 3);
NRFX_IRQ_ENABLE(SlowTicker_IRQn);
}
void ticker_register_low_pri_callback(callback_ptr slow_ticker_callback) {
m_slow_tickers[m_num_of_slow_tickers++] = slow_ticker_callback;
}
/* Start and stop timer 1 including workarounds for Anomaly 73 for Timer
* http://www.nordicsemi.com/eng/content/download/29490/494569/file/nRF51822-PAN%20v3.0.pdf
*/
void ticker_start(void) {
NRFX_IRQ_ENABLE(FastTicker_IRQn);
#ifdef NRF51
*(uint32_t *)0x40009C0C = 1; // for Timer 1
#endif
FastTicker->TASKS_START = 1;
}
void ticker_stop(void) {
NRFX_IRQ_DISABLE(FastTicker_IRQn);
FastTicker->TASKS_STOP = 1;
#ifdef NRF51
*(uint32_t *)0x40009C0C = 0; // for Timer 1
#endif
}
int32_t noop(void) {
return -1;
}
volatile uint32_t ticks;
static ticker_callback_ptr callbacks[3] = { noop, noop, noop };
void FastTicker_IRQHandler(void) {
NRF_TIMER_Type *ticker = FastTicker;
ticker_callback_ptr *call = callbacks;
if (ticker->EVENTS_COMPARE[0]) {
ticker->EVENTS_COMPARE[0] = 0;
ticker->CC[0] += call[0]()*MICROSECONDS_PER_TICK;
}
if (ticker->EVENTS_COMPARE[1]) {
ticker->EVENTS_COMPARE[1] = 0;
ticker->CC[1] += call[1]()*MICROSECONDS_PER_TICK;
}
if (ticker->EVENTS_COMPARE[2]) {
ticker->EVENTS_COMPARE[2] = 0;
ticker->CC[2] += call[2]()*MICROSECONDS_PER_TICK;
}
if (ticker->EVENTS_COMPARE[3]) {
ticker->EVENTS_COMPARE[3] = 0;
ticker->CC[3] += MICROSECONDS_PER_MACRO_TICK;
ticks += MILLISECONDS_PER_MACRO_TICK;
NRFX_IRQ_PENDING_SET(SlowTicker_IRQn);
}
}
static const uint32_t masks[3] = {
TIMER_INTENCLR_COMPARE0_Msk,
TIMER_INTENCLR_COMPARE1_Msk,
TIMER_INTENCLR_COMPARE2_Msk,
};
int set_ticker_callback(uint32_t index, ticker_callback_ptr func, int32_t initial_delay_us) {
if (index > 3)
return -1;
NRF_TIMER_Type *ticker = FastTicker;
callbacks[index] = noop;
ticker->INTENCLR = masks[index];
ticker->TASKS_CAPTURE[index] = 1;
uint32_t t = FastTicker->CC[index];
// Need to make sure that set tick is aligned to lastest tick
// Use CC[3] as a reference, as that is always up-to-date.
int32_t cc3 = FastTicker->CC[3];
int32_t delta = t+initial_delay_us-cc3;
delta = (delta/MICROSECONDS_PER_TICK+1)*MICROSECONDS_PER_TICK;
callbacks[index] = func;
ticker->INTENSET = masks[index];
FastTicker->CC[index] = cc3 + delta;
return 0;
}
int clear_ticker_callback(uint32_t index) {
if (index > 3)
return -1;
FastTicker->INTENCLR = masks[index];
callbacks[index] = noop;
return 0;
}
void SlowTicker_IRQHandler(void)
{
for (int i = 0; i < m_num_of_slow_tickers; i++) {
if (m_slow_tickers[i] != NULL) {
m_slow_tickers[i]();
}
}
}
#endif // MICROPY_PY_MACHINE_SOFT_PWM