How To Use Rtc - Espressif Systems ESP8266EX Programming Manual

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3. Compile the application program, generate firmware and download it into the ESP8266
module.
4. Power off the module, and change it to operation mode; then power on the module and
run the program.
Result:
read data from 0x3E000 : 05 00 04 02

3.2.10. How to Use RTC

1. When software restart (system_restart) is executed, the system time will return to zero,
while the RTC timer will continue. However, if the chip is woken up (including being
periodically woken up from Deep-sleep mode) via external hardware (including EXT_RST
pin or CHIP_EN pin), the RTC timer will be restarted.
external reset (EXT_RST): the RTC memory does not change; the register of the RTC
•
timer counts from zero.
watchdog reset: the RTC memory does not change; the register of the RTC timer
•
does not change.
• system_restart: the RTC memory does not change; the register of the RTC timer
does not change.
Power on: the value of the RTC memory is random; the register of the RTC timer
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counts from zero.
• CHIP_EN reset: the value of the RTC memory is random; the register of the RTC
timer counts from zero.
For example, if the returned value of system_get_rtc_time is 10 (indicating 10 RTC
cycles), and the returned value of system_rtc_clock_cali_proc is 5.75 μs (indicating
that the duration of one RTC cycle is 5.75 microseconds), then the real time will be
10x5.75 = 57.5 microseconds.
rtc_t = system_get_rtc_time();
cal = system_rtc_clock_cali_proc();
os_printf("cal: %d.%d \r\n", ((cal*1000)>>12)/1000, ((cal*1000)>>12)%1000 );
Read and write RTC memory. Please note that RTC memory access must be four-byte
aligned.
typedef struct {
uint64 time_acc;
uint32 magic ;
uint32 time_base;
} RTC_TIMER_DEMO;
system_rtc_mem_read(64, &rtc_time, sizeof(rtc_time));
2. Compile the application program, generate firmware and download it into the ESP8266
module.
Espressif 14 37 ! /!
3. Sample Codes
2017.05