timer_esp8266.cpp

// ---------------------------------------------
//           This file is part of
//      _  _   __    _   _    __    __
//     ( \/ ) /__\  ( )_( )  /__\  (  )
//      \  / /(__)\  ) _ (  /(__)\  )(__
//      (__)(__)(__)(_) (_)(__)(__)(____)
//
//     Yet Another HW Abstraction Library
//      Copyright (C) Andreas Terstegge
//      BSD Licensed (see file LICENSE)
//
// ---------------------------------------------
//
// Timer implementation for ESP8266.
//
#include "timer_esp8266.h"
#include "ESP8266.h"
#include <cassert>
 
extern "C" {
#include "ets_sys.h"
}
 
timer_esp8266::timer_esp8266() {
    _TIMER_::TIMER.FRC1_CTRL = 0;
    _period_us   = 0;
    _period_load = 0;
    _divider     = 1;
}
 
timer_esp8266::~timer_esp8266() {
    _TIMER_::TIMER.FRC1_CTRL = 0;    // stop the timer and
    TM1_EDGE_INT_DISABLE();          // disable the interrupts
    ETS_FRC1_INTR_DISABLE();
}
 
void timer_esp8266::setPeriod(uint32_t us, TIMER::timer_mode mode) {
    _TIMER_::TIMER.FRC1_CTRL.RELOAD = (mode == TIMER::PERIODIC); // ? 1 : 0);
    // Start with divider = 1
    _period_us   = us;
    _period_load = 80 * us;
    _divider     = 1;
    _TIMER_::TIMER.FRC1_CTRL.DIVIDER = _TIMER_::FRC1_CTRL_DIVIDER__1;
    // check if we need a divider = 16
    if (_period_load > 0x7fffff) {
        _period_load /= 16;
        _divider     *= 16;
        _TIMER_::TIMER.FRC1_CTRL.DIVIDER = _TIMER_::FRC1_CTRL_DIVIDER__16;
        // even a divider = 256 ?
        if (_period_load > 0x7fffff) {
            _period_load /= 16;
            _divider     *= 16;
            _TIMER_::TIMER.FRC1_CTRL.DIVIDER = _TIMER_::FRC1_CTRL_DIVIDER__256;
        }
    }
    // the period should be in the valid range now
    assert(_period_load <= 0x7fffff);
    _TIMER_::TIMER.FRC1_LOAD = _period_load;
}
 
uint32_t timer_esp8266::getPeriod() {
    return _period_us;
}
 
void timer_esp8266::setCallback(function<void()> f) {
    _handler = f;
    _TIMER_::TIMER.FRC1_CTRL.INT_TYPE = _TIMER_::FRC1_CTRL_INT_TYPE__EDGE;
    ETS_FRC_TIMER1_INTR_ATTACH(timer_irq_handler, this);
    TM1_EDGE_INT_ENABLE();
    ETS_FRC1_INTR_ENABLE();
}
 
void timer_esp8266::start() {
    _TIMER_::TIMER.FRC1_CTRL.ENABLE = 1;
}
 
void timer_esp8266::stop() {
    _TIMER_::TIMER.FRC1_CTRL.ENABLE = 0;
}
 
bool timer_esp8266::isRunning() {
    return _TIMER_::TIMER.FRC1_CTRL.ENABLE;
}
 
uint32_t timer_esp8266::getCounter() {
    return (_period_load - _TIMER_::TIMER.FRC1_COUNT) * _divider / 80;
}
 
void timer_esp8266::resetCounter() {
    _TIMER_::TIMER.FRC1_LOAD = _period_load;
}
 
void timer_irq_handler(timer_esp8266 *timer) {
    if(timer->_handler) timer->_handler();
}