acidburns
2199627a35
- Track last OLED activity to avoid double timeout; keep power gating on transitions - Copy TZ before setenv() in timegm_fallback to avoid invalid pointer reuse - Add BATTERY_SAMPLE_INTERVAL_MS and only refresh cache at batch start when due - Keep battery sampling to a single ADC read (Arduino core lacks explicit ADC power gating)
126 lines
3.2 KiB
C++
126 lines
3.2 KiB
C++
#include "rtc_ds3231.h"
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#include "config.h"
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#include <Wire.h>
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#include <string>
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#include <time.h>
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static constexpr uint8_t DS3231_ADDR = 0x68;
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static uint8_t bcd_to_dec(uint8_t val) {
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return static_cast<uint8_t>((val >> 4) * 10 + (val & 0x0F));
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}
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static uint8_t dec_to_bcd(uint8_t val) {
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return static_cast<uint8_t>(((val / 10) << 4) | (val % 10));
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}
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static time_t timegm_fallback(struct tm *tm_utc) {
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if (!tm_utc) {
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return static_cast<time_t>(-1);
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}
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const char *old_tz = getenv("TZ");
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// getenv() may return a pointer into mutable storage that becomes invalid after setenv().
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std::string old_tz_copy = old_tz ? old_tz : "";
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setenv("TZ", "UTC0", 1);
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tzset();
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time_t t = mktime(tm_utc);
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if (!old_tz_copy.empty()) {
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setenv("TZ", old_tz_copy.c_str(), 1);
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} else {
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unsetenv("TZ");
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}
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tzset();
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return t;
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}
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static bool read_registers(uint8_t start_reg, uint8_t *out, size_t len) {
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if (!out || len == 0) {
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return false;
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}
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Wire.beginTransmission(DS3231_ADDR);
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Wire.write(start_reg);
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if (Wire.endTransmission(false) != 0) {
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return false;
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}
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size_t read = Wire.requestFrom(DS3231_ADDR, static_cast<uint8_t>(len));
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if (read != len) {
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return false;
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}
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for (size_t i = 0; i < len; ++i) {
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out[i] = Wire.read();
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}
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return true;
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}
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static bool write_registers(uint8_t start_reg, const uint8_t *data, size_t len) {
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if (!data || len == 0) {
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return false;
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}
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Wire.beginTransmission(DS3231_ADDR);
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Wire.write(start_reg);
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for (size_t i = 0; i < len; ++i) {
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Wire.write(data[i]);
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}
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return Wire.endTransmission() == 0;
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}
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bool rtc_ds3231_init() {
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Wire.begin(PIN_OLED_SDA, PIN_OLED_SCL);
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Wire.setClock(100000);
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return rtc_ds3231_is_present();
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}
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bool rtc_ds3231_is_present() {
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Wire.beginTransmission(DS3231_ADDR);
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return Wire.endTransmission() == 0;
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}
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bool rtc_ds3231_read_epoch(uint32_t &epoch_utc) {
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uint8_t regs[7] = {};
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if (!read_registers(0x00, regs, sizeof(regs))) {
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return false;
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}
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uint8_t sec = bcd_to_dec(regs[0] & 0x7F);
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uint8_t min = bcd_to_dec(regs[1] & 0x7F);
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uint8_t hour = bcd_to_dec(regs[2] & 0x3F);
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uint8_t day = bcd_to_dec(regs[4] & 0x3F);
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uint8_t month = bcd_to_dec(regs[5] & 0x1F);
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uint16_t year = 2000 + bcd_to_dec(regs[6]);
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struct tm tm_utc = {};
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tm_utc.tm_sec = sec;
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tm_utc.tm_min = min;
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tm_utc.tm_hour = hour;
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tm_utc.tm_mday = day;
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tm_utc.tm_mon = month - 1;
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tm_utc.tm_year = year - 1900;
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tm_utc.tm_isdst = 0;
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time_t t = timegm_fallback(&tm_utc);
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if (t <= 0) {
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return false;
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}
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epoch_utc = static_cast<uint32_t>(t);
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return true;
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}
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bool rtc_ds3231_set_epoch(uint32_t epoch_utc) {
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time_t t = static_cast<time_t>(epoch_utc);
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struct tm tm_utc = {};
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if (!gmtime_r(&t, &tm_utc)) {
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return false;
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}
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uint8_t regs[7] = {};
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regs[0] = dec_to_bcd(static_cast<uint8_t>(tm_utc.tm_sec));
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regs[1] = dec_to_bcd(static_cast<uint8_t>(tm_utc.tm_min));
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regs[2] = dec_to_bcd(static_cast<uint8_t>(tm_utc.tm_hour));
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regs[3] = dec_to_bcd(static_cast<uint8_t>(tm_utc.tm_wday + 1));
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regs[4] = dec_to_bcd(static_cast<uint8_t>(tm_utc.tm_mday));
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regs[5] = dec_to_bcd(static_cast<uint8_t>(tm_utc.tm_mon + 1));
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regs[6] = dec_to_bcd(static_cast<uint8_t>((tm_utc.tm_year + 1900) - 2000));
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return write_registers(0x00, regs, sizeof(regs));
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}
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