RTC Battery

Edge 2 has an HYM8563 real-time clock on its I²C3 bus, with a coin-cell holder on the top side of the board. With a coin cell fitted, the HYM8563 keeps running while the board has no power.

Figure 1. The coin-cell holder

Fit the Coin Cell

1. Shut down Edge 2 and disconnect the power supply.
2. Slide the coin cell into the holder with the + side facing up, away from the board.
3. Reconnect the power supply.

The Clocks on the Board

Edge 2 has two real-time clocks:

Clock	Where	Kept without power
HYM8563	On I2C3, at address 0x51, with the coin-cell holder	Yes, with a coin cell fitted
RTC of the RK809 power-management chip	On the Core 3568 module	No

Which clock the operating system reads at startup depends on the operating system. For the behaviour of Mixtile OS and how to read and set the HYM8563 there, see Real-Time Clocks.