4.15. Real Time Clock, RTC
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.
Table 4.44. RTC implementation
| 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).
PDF version