initialize repository

ds1302.c

@@ -0,0 +1,162 @@
+#include "ds1302.h"
+
+void _prepare_read(uint8_t address);
+void _prepare_write(uint8_t address);
+uint8_t _read_byte();
+void _write_byte(uint8_t value);
+void _make_clock_cycle();
+
+void _end_transfer();
+
+#define REG_SECONDS 0x80 // SEC
+#define REG_MINUTES 0x82 // MIN
+#define REG_HOUR 0x84    // HR
+#define REG_DATE 0x86    // DATE
+#define REG_MONTH 0x88   // MONTH
+#define REG_DAY 0x8A     // DAY
+#define REG_YEAR 0x8C    // YEAR
+#define REG_WP 0x8E      // CONTROL
+// TRICKLE CHARGER 1001000_ 0x90
+#define REG_BURST 0xBE // CLOCK BURST
+
+#define REG_RAM00 0xC0
+#define REG_RAM_BURST 0xFE
+
+void ds1302_init() {
+  gpio_init(PIN_RTC_RESET);
+  gpio_set_dir(PIN_RTC_RESET, GPIO_OUT);
+  gpio_put(PIN_RTC_RESET, LOW);
+
+  gpio_init(PIN_RTC_CLOCK);
+  gpio_set_dir(PIN_RTC_CLOCK, GPIO_OUT);
+  gpio_put(PIN_RTC_CLOCK, LOW);
+
+  gpio_init(PIN_RTC_IO);
+  gpio_set_dir(PIN_RTC_IO, GPIO_IN);
+}
+
+int ds1302_is_clock_halted() {
+  _prepare_read(REG_SECONDS);
+  uint8_t seconds = _read_byte();
+  _end_transfer();
+  return (seconds & 0b10000000);
+}
+
+void ds1302_get_datetime(DateTime *dt) {
+  _prepare_read(REG_BURST);
+  dt->second = ds1302_decode_bcd(_read_byte() & 0b01111111);
+  dt->minute = ds1302_decode_bcd(_read_byte() & 0b01111111);
+  dt->hour = ds1302_decode_bcd(_read_byte() & 0b00111111);
+  dt->day = ds1302_decode_bcd(_read_byte() & 0b00111111);
+  dt->month = ds1302_decode_bcd(_read_byte() & 0b00011111);
+  dt->dow = ds1302_decode_bcd(_read_byte() & 0b00000111);
+  dt->year = ds1302_decode_bcd(_read_byte() & 0b01111111);
+  _end_transfer();
+}
+
+void ds1302_set_datetime(DateTime *dt) {
+  // disable write protection
+  _prepare_write(REG_WP);
+  _write_byte(0b00000000); // 0, false
+  _end_transfer();
+  // OR call writeProtect(0)
+
+  _prepare_write(REG_BURST);
+  _write_byte(ds1302_encode_bcd(dt->second % 60));
+  _write_byte(ds1302_encode_bcd(dt->minute % 60));
+  _write_byte(ds1302_encode_bcd(dt->hour % 24));
+  _write_byte(ds1302_encode_bcd(dt->day % 32));
+  _write_byte(ds1302_encode_bcd(dt->month % 13));
+  _write_byte(ds1302_encode_bcd(dt->dow % 8));
+  _write_byte(ds1302_encode_bcd(dt->year % 100));
+  _write_byte(0b10000000);
+  _end_transfer();
+}
+
+void ds1302_halt() {
+  _prepare_write(REG_SECONDS);
+  _write_byte(0b10000000);
+  _end_transfer();
+}
+
+void _prepare_read(uint8_t address) {
+  gpio_set_dir(PIN_RTC_IO, GPIO_OUT);
+  gpio_put(PIN_RTC_RESET, HIGH);
+  uint8_t command = 0b10000001 | address;
+  _write_byte(command);
+  gpio_set_dir(PIN_RTC_IO, GPIO_IN);
+}
+
+void _prepare_write(uint8_t address) {
+  gpio_set_dir(PIN_RTC_IO, GPIO_OUT);
+  gpio_put(PIN_RTC_RESET, HIGH);
+  uint8_t command = 0b10000000 | address;
+  _write_byte(command);
+}
+
+void _end_transfer() { gpio_put(PIN_RTC_RESET, LOW); }
+
+uint8_t _read_byte() {
+  uint8_t byte = 0;
+  for (uint8_t b = 0; b < 8; b++) {
+    if (gpio_get(PIN_RTC_IO) == HIGH)
+      byte |= 0x01 << b;
+    _make_clock_cycle();
+  }
+  return byte;
+}
+
+void _write_byte(uint8_t value) {
+  for (uint8_t b = 0; b < 8; b++) {
+    gpio_put(PIN_RTC_IO, (value & 0x01) ? HIGH : LOW);
+    _make_clock_cycle();
+    value >>= 1;
+  }
+}
+
+void _make_clock_cycle() {
+  gpio_put(PIN_RTC_CLOCK, HIGH);
+  sleep_us(1);
+  gpio_put(PIN_RTC_CLOCK, LOW);
+  sleep_us(1);
+}
+
+void ds1302_get_ram_byte(uint8_t addr, uint8_t *data) {
+  _prepare_read(addr);
+  *data = _read_byte();
+  _end_transfer();
+}
+
+void ds1302_set_ram_byte(uint8_t addr, uint8_t *data) {
+  _prepare_write(addr);
+  _write_byte(*data);
+  _end_transfer();
+}
+
+void ds1302_set_write_protection(int enable) {
+  _prepare_write(REG_WP);
+  _write_byte(enable);
+  _end_transfer();
+}
+
+void ds1302_write_ram_bulk(const uint8_t *data, int len) {
+  if (len <= 0 || len > 31) {
+    return;
+  }
+  _prepare_write(REG_RAM_BURST);
+  for (int i = 0; i < len; i++) {
+    _write_byte(data[i]);
+  }
+  _end_transfer();
+}
+
+void ds1302_read_ram_bulk(uint8_t *data, int len) {
+  if (len <= 0 || len > 31) {
+    return;
+  }
+  _prepare_read(REG_RAM_BURST);
+  for (int i = 0; i < len; i++) {
+    data[i] = _read_byte();
+  }
+  _end_transfer();
+}