timer.c

/*
 * This file is part of the W1209 firmware replacement project
 * (https://github.com/mister-grumbler/w1209-firmware).
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, version 3.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

/**
 * Control functions for timer.
 * The TIM4 interrupt (23) is used to get signal on update event.
 */

#include "timer.h"
#include "stm8s003/clock.h"
#include "stm8s003/timer.h"
#include "adc.h"
#include "display.h"
#include "menu.h"
#include "relay.h"

#define TICKS_IN_SECOND     500
#define BITS_FOR_TICKS      9
#define BITS_FOR_SECONDS    6
#define BITS_FOR_MINUTES    6
#define BITS_FOR_HOURS      5
#define BITS_FOR_DAYS       6
#define SECONDS_FIRST_BIT   BITS_FOR_TICKS + 1
#define MINUTES_FIRST_BIT   BITS_FOR_TICKS + BITS_FOR_SECONDS + 1
#define HOURS_FIRST_BIT     BITS_FOR_TICKS + BITS_FOR_SECONDS + BITS_FOR_MINUTES + 1
#define DAYS_FIRST_BIT      BITS_FOR_TICKS + BITS_FOR_SECONDS + BITS_FOR_MINUTES + BITS_FOR_HOURS + 1
#define BITMASK(L)          ( ~ (0xFFFFFFFF << (L) ) )
#define NBITMASK(L)         (0xFFFFFFFF << (L) )

/**
 * Uptime counter
 * |--Day--|--Hour--|--Minute--|--Second--|--Ticks--|
 * 31      26       21         15         9         0
 */
static unsigned long uptime;

/**
 * @brief Initialize timer's configuration registers and reset uptime.
 */
void initTimer()
{
    CLK_CKDIVR = 0x00;  // Set the frequency to 16 MHz
    TIM4_PSCR = 0x07;   // CLK / 128 = 125KHz
    TIM4_ARR = 0xFA;    // 125KHz /  250(0xFA) = 500Hz
    TIM4_IER = 0x01;    // Enable interrupt on update event
    TIM4_CR1 = 0x05;    // Enable timer
    resetUptime();
}

/**
 * @brief Sets value of uptime counter to zero.
 */
void resetUptime()
{
    uptime = 0;
}

/**
 * @brief Gets raw value of bit-mapped uptime counter.
 * |--Day--|--Hour--|--Minute--|--Second--|--Ticks--|
 * 31      26       21         15         9         0
 * @return value of uptime counter.
 */
unsigned long getUptime()
{
    return uptime;
}

/**
 * @brief Gets ticks part of uptime counter.
 * @return ticks part of uptime.
 */
unsigned int getUptimeTicks()
{
    return (unsigned int) (uptime & BITMASK (BITS_FOR_TICKS) );
}

/**
 * @brief Gets seconds part of time being passed since last reset.
 * @return seconds part of uptime.
 */
unsigned char getUptimeSeconds()
{
    return (unsigned char) ( (uptime >> SECONDS_FIRST_BIT) & BITMASK (BITS_FOR_SECONDS) );
}

/**
 * @brief Gets minutes part of time being passed since last reset.
 * @return minutes part of uptime.
 */
unsigned char getUptimeMinutes()
{
    return (unsigned char) ( (uptime >> MINUTES_FIRST_BIT) & BITMASK (BITS_FOR_MINUTES) );
}

/**
 * @brief Gets hours part of time being passed since last reset.
 * @return hours part of uptime.
 */
unsigned char getUptimeHours()
{
    return (unsigned char) ( (uptime >> HOURS_FIRST_BIT) & BITMASK (BITS_FOR_HOURS) );
}

/**
 * @brief Gets amount of days being passed since last reset.
 * @return amount of days.
 */
unsigned char getUptimeDays()
{
    return (unsigned char) ( (uptime >> DAYS_FIRST_BIT) & BITMASK (BITS_FOR_DAYS) );
}

/**
 * @brief This function is timer's interrupt request handler
 * so keep it small and fast as much as possible.
 */
void TIM4_UPD_handler() __interrupt (23)
{
    TIM4_SR &= ~TIM_SR1_UIF; // Reset flag

    if ( ( (unsigned int) (uptime & BITMASK (BITS_FOR_TICKS) ) ) >= TICKS_IN_SECOND) {
        uptime &= NBITMASK (SECONDS_FIRST_BIT);
        uptime += (unsigned long) 1 << SECONDS_FIRST_BIT;

        // Increment minutes count when 60 seconds have passed.
        if ( ( (unsigned char) (uptime >> SECONDS_FIRST_BIT) & BITMASK (BITS_FOR_SECONDS) ) == 60) {
            uptime &= NBITMASK (MINUTES_FIRST_BIT);
            uptime += (unsigned long) 1 << MINUTES_FIRST_BIT;
        }

        // Increment hours count when 60 minutes have passed.
        if ( ( (unsigned char) (uptime >> MINUTES_FIRST_BIT) & BITMASK (BITS_FOR_MINUTES) ) == 60) {
            uptime &= NBITMASK (HOURS_FIRST_BIT);
            uptime += (unsigned long) 1 << HOURS_FIRST_BIT;
        }

        // Increment days count when 24 hours have passed.
        if ( ( (unsigned char) (uptime >> HOURS_FIRST_BIT) & BITMASK (BITS_FOR_HOURS) ) == 24) {
            uptime &= NBITMASK (DAYS_FIRST_BIT);
            uptime += (unsigned long) 1 << DAYS_FIRST_BIT;
        }
    }

    uptime++;

    // Try not to call all refresh functions at once.
    if ( ( (unsigned char) getUptimeTicks() & 0x0F) == 1) {
        refreshMenu();
    } else if ( ( (unsigned char) getUptimeTicks() & 0xFF) == 2) {
        startADC();
    } else if ( ( (unsigned char) getUptimeTicks() & 0xFF) == 3) {
        refreshRelay();
    }

    refreshDisplay();
}