The PL031 PrimeCell Real Time Clock Controller (RTC) is an AMBA compliant SoC peripheral that is developed, tested, and licensed by ARM Limited.
A counter in the RTC is incremented every second. The RTC can therefore be used as a basic alarm function or long time-base counter.
The current value of the clock can be read at any time or the RTC can be programmed to generate an interrupt after counting for a programmed number of seconds. The interrupt can be masked by writing to the interrupt match set or clear register.
| Property | Value |
|---|---|
| Location | Southbridge |
| Memory base address | 0x10017000 |
| Interrupt | 42 |
| DMA | − |
| Release version | ARM RTC PL031 r1p0 |
| Reference documentation | ARM PrimeCell Real Time Clock (PL031) Technical Reference Manual |
Note
There is also a separate Time-of-Year (TOY) implemented in
an external RTC chip (DS1338) on the baseboard. The external RTC
can be accessed by the serial bus interface (see Two-wire serial bus interface, SBCon). For details
on the programming interface to the Time-of-Year RTC, see the data
sheet for the Maxim DS1338 integrated circuit (www.maxim-ic.com).