2.5. Real Time Clock

The Real Time Clock (RTC) is connected to the ML675001 on the I2C bus. The RTC is a Ricoh R2051 with a 32KHz crystal attached. This device has the capacity to hold the date and time and keep time using a minimum of power, typically 0.4uA with 3V supply.

There is also the ability to set alarms which may generate interrupts, this may be used to perform repeating tasks with long intervals without consuming large amounts of power.

The R2051 interrupt is connected to the ML675001 IRQ0. This IRQ is shared with the Davicom ethernet controller and is also present on A13 of the PL4 connector.