164 lines
3.6 KiB
C
164 lines
3.6 KiB
C
/*
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* Driver for DS1307 RTC
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*
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* Part of esp-open-rtos
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* Copyright (C) 2016 Ruslan V. Uss <unclerus@gmail.com>
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* BSD Licensed as described in the file LICENSE
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*/
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#include "ds1307.h"
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#include <i2c/i2c.h>
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#include <stdio.h>
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#define ADDR 0x68
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#define RAM_SIZE 56
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#define TIME_REG 0
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#define CONTROL_REG 7
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#define RAM_REG 8
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#define CH_BIT (1 << 7)
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#define HOUR12_BIT (1 << 6)
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#define PM_BIT (1 << 5)
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#define SQWE_BIT (1 << 4)
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#define OUT_BIT (1 << 7)
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#define CH_MASK 0x7f
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#define SECONDS_MASK 0x7f
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#define HOUR12_MASK 0x1f
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#define HOUR24_MASK 0x3f
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#define SQWEF_MASK 0x03
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#define SQWE_MASK 0xef
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#define OUT_MASK 0x7f
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static uint8_t bcd2dec(uint8_t val)
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{
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return (val >> 4) * 10 + (val & 0x0f);
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}
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static uint8_t dec2bcd(uint8_t val)
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{
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return ((val / 10) << 4) + (val % 10);
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}
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static uint8_t read_register(uint8_t reg)
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{
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uint8_t val;
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i2c_slave_read(ADDR, reg, &val, 1);
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return val;
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}
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static void update_register(uint8_t reg, uint8_t mask, uint8_t val)
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{
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uint8_t buf[2];
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buf[0] = reg;
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buf[1] = (read_register(reg) & mask) | val;
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i2c_slave_write(ADDR, buf, 2);
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}
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void ds1307_start(bool start)
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{
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update_register(TIME_REG, CH_MASK, start ? 0 : CH_BIT);
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}
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bool ds1307_is_running()
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{
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return !(read_register(TIME_REG) & CH_BIT);
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}
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void ds1307_get_time(struct tm *time)
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{
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uint8_t buf[7];
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i2c_slave_read(ADDR, TIME_REG, buf, 7);
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time->tm_sec = bcd2dec(buf[0] & SECONDS_MASK);
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time->tm_min = bcd2dec(buf[1]);
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if (buf[2] & HOUR12_BIT)
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{
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// RTC in 12-hour mode
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time->tm_hour = bcd2dec(buf[2] & HOUR12_MASK) - 1;
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if (buf[2] & PM_BIT)
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time->tm_hour += 12;
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}
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else time->tm_hour = bcd2dec(buf[2] & HOUR24_MASK);
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time->tm_wday = bcd2dec(buf[3]) - 1;
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time->tm_mday = bcd2dec(buf[4]);
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time->tm_mon = bcd2dec(buf[5]) - 1;
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time->tm_year = bcd2dec(buf[6]) + 2000;
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}
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void ds1307_set_time(const struct tm *time)
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{
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uint8_t buf[8];
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buf[0] = TIME_REG;
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buf[1] = dec2bcd(time->tm_sec);
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buf[2] = dec2bcd(time->tm_min);
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buf[3] = dec2bcd(time->tm_hour);
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buf[4] = dec2bcd(time->tm_wday);
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buf[5] = dec2bcd(time->tm_mday);
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buf[6] = dec2bcd(time->tm_mon);
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buf[7] = dec2bcd(time->tm_year - 2000);
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i2c_slave_write(ADDR, buf, 8);
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}
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void ds1307_enable_squarewave(bool enable)
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{
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update_register(CONTROL_REG, SQWE_MASK, enable ? SQWE_BIT : 0);
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}
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bool ds1307_is_squarewave_enabled()
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{
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return read_register(CONTROL_REG) & SQWE_BIT;
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}
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void ds1307_set_squarewave_freq(ds1307_squarewave_freq_t freq)
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{
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update_register(CONTROL_REG, SQWEF_MASK, (uint8_t)freq);
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}
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ds1307_squarewave_freq_t ds1307_get_squarewave_freq()
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{
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return (ds1307_squarewave_freq_t)(read_register(CONTROL_REG) & SQWEF_MASK);
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}
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bool ds1307_get_output()
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{
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return read_register(CONTROL_REG) & OUT_BIT;
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}
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void ds1307_set_output(bool value)
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{
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update_register(CONTROL_REG, OUT_MASK, value ? OUT_BIT : 0);
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}
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bool ds1307_read_ram(uint8_t offset, uint8_t *buf, uint8_t len)
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{
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if (offset + len > RAM_SIZE) return false;
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return i2c_slave_read(ADDR, RAM_REG + offset, buf, len);
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}
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bool ds1307_write_ram(uint8_t offset, uint8_t *buf, uint8_t len)
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{
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if (offset + len > RAM_SIZE) return false;
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// temporary buffer on the stack is not good so copy-paste :(
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bool success = false;
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do {
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i2c_start();
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if (!i2c_write(ADDR << 1))
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break;
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if (!i2c_write(RAM_REG + offset))
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break;
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while (len--) {
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if (!i2c_write(*buf++))
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break;
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}
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i2c_stop();
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success = true;
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} while(0);
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return success;
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}
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