DS1307 RTC driver + example

examples/ds1307/Makefile

@@ -0,0 +1,3 @@
+PROGRAM = ds1307
+EXTRA_COMPONENTS = extras/i2c extras/ds1307
+include ../../common.mk

examples/ds1307/main.c

@@ -0,0 +1,45 @@
+/*
+ * Example of using DS1307 RTC driver
+ *
+ * Part of esp-open-rtos
+ * Copyright (C) 2016 Ruslan V. Uss <unclerus@gmail.com>
+ * BSD Licensed as described in the file LICENSE
+ */
+#include <esp/uart.h>
+#include <espressif/esp_common.h>
+#include <i2c/i2c.h>
+#include <ds1307/ds1307.h>
+#include <stdio.h>
+
+#define SCL_PIN 5
+#define SDA_PIN 4
+
+void user_init (void)
+{
+    uart_set_baud (0, 115200);
+    printf ("SDK version:%s\n", sdk_system_get_sdk_version ());
+
+    i2c_init (SCL_PIN, SDA_PIN);
+    ds1307_start (true);
+
+    // setup datetime: 2016-10-09 13:50:10
+    struct tm time = {
+        .tm_year = 2016,
+        .tm_mon = 10,
+        .tm_mday = 9,
+        .tm_hour = 13,
+        .tm_min = 50,
+        .tm_sec = 10
+    };
+    ds1307_set_time (&time);
+
+    while (true)
+    {
+        ds1307_get_time (&time);
+
+        printf ("%04d-%02d-%02d %02d:%02d:%02d\n", time.tm_year, time.tm_mon, time.tm_mday, time.tm_hour, time.tm_min, time.tm_sec);
+
+        for (uint32_t i = 0; i < 1000; i ++)
+            sdk_os_delay_us (500);
+    }
+}

extras/ds1307/component.mk

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+# Component makefile for extras/ds1307
+
+# expected anyone using RTC driver includes it as 'ds1307/ds1307.h'
+INC_DIRS += $(ds1307_ROOT)..
+
+# args for passing into compile rule generation
+ds1307_SRC_DIR =  $(ds1307_ROOT)
+
+$(eval $(call component_compile_rules,ds1307))

extras/ds1307/ds1307.c

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

extras/ds1307/ds1307.h

@@ -0,0 +1,114 @@
+/*
+ * Driver for DS1307 RTC
+ *
+ * Part of esp-open-rtos
+ * Copyright (C) 2016 Ruslan V. Uss <unclerus@gmail.com>
+ * BSD Licensed as described in the file LICENSE
+ */
+#ifndef EXTRAS_DS1307_H_
+#define EXTRAS_DS1307_H_
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <time.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * Squarewave frequency
+ */
+typedef enum _ds1307_squarewave_freq_t
+{
+    DS1307_1HZ = 0, //!< 1 Hz
+    DS1307_4096HZ,  //!< 4096 Hz
+    DS1307_8192HZ,  //!< 8192 Hz
+    DS1307_32768HZ  //!< 32768 Hz
+} ds1307_squarewave_freq_t;
+
+/**
+ * \brief Start/stop clock
+ * \param start Start clock if true
+ */
+void ds1307_start(bool start);
+
+/**
+ * \brief Get current clock state
+ * \return true if clock running
+ */
+bool ds1307_is_running();
+
+/**
+ * \brief Get current time
+ * \param time Pointer to the time struct to fill
+ */
+void ds1307_get_time(struct tm *time);
+
+/**
+ * \brief Set time to RTC
+ * \param time Pointer to the time struct
+ */
+void ds1307_set_time(const struct tm *time);
+
+/**
+ * \brief Enable or disable square-wave oscillator output
+ * \param enable Enable oscillator if true
+ */
+void ds1307_enable_squarewave(bool enable);
+
+/**
+ * \brief Get square-wave oscillator output
+ * \return true if square-wave oscillator enabled
+ */
+bool ds1307_is_squarewave_enabled();
+
+/**
+ * \brief Set square-wave oscillator frequency
+ * \param freq Frequency
+ */
+void ds1307_set_squarewave_freq(ds1307_squarewave_freq_t freq);
+
+/**
+ * \brief Get current square-wave oscillator frequency
+ * \return Frequency
+ */
+ds1307_squarewave_freq_t ds1307_get_squarewave_freq();
+
+/**
+ * \brief Get current output level of the SQW/OUT pin
+ * \return true if high
+ */
+bool ds1307_get_output();
+
+/**
+ * \brief Set output level of the SQW/OUT pin
+ * Set output level if square-wave output is disabled
+ * \param value High level if true
+ */
+void ds1307_set_output(bool value);
+
+/**
+ * \brief Read RAM contents into the buffer
+ * \param offset Start byte, 0..55
+ * \param buf Buffer
+ * \param len Bytes to read, 1..56
+ * \return false if error occured
+ */
+bool ds1307_read_ram(uint8_t offset, uint8_t *buf, uint8_t len);
+
+/**
+ * \brief Write buffer to RTC RAM
+ * \param offset Start byte, 0..55
+ * \param buf Buffer
+ * \param len Bytes to write, 1..56
+ * \return false if error occured
+ */
+bool ds1307_write_ram(uint8_t offset, uint8_t *buf, uint8_t len);
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* EXTRAS_DS1307_H_ */