RTC – Real-Time Clock. Counts Seconds, Minutes, Hours, Date of the Month, Month, Day of the Week, and Year with Leap-Year. Compensation Valid Up to 2100.
24-hour or 12-hour format
The contents of the time and calendar registers are in the BCD format. BCD – binary-coded decimal
I2C serial interface. Slave device. Operates in the standard mode (100kHz) only.
Address (7-bit) 1101000 = 0x68 followed by the direction bit (R/W).
Write address (8-bit) 11010000 = 0xD0
Read address (8-bit) 11010001 = 0xD1
Has a built-in power-sense circuit that detects power failures and automatically switches to the backup supply.
56-Byte, Battery-Backed, General-Purpose SRAM with Unlimited Writes
Programmable Square-Wave Output Signal
Consumes Less than 500nA in Battery-Backup Mode with Oscillator Running
RTC and RAM address map
RTC registers 0x00 to 0x07
SRAM registers 0x08 to 0x3F
BIT 7: CH – clock halt pit. When set to 1, the oscillator is disabled.
01/01/00 01 00:00:00 (MM/DD/YY DOW HH:MM:SS)
BIT 6: 1 – 12-hour mode, 0 – 24-hour mode
Testing It with CH32V003
Project code: https://github.com/taunoe/RTC_aeg
Tauno Erik 