Artesyn MVME8100/MVME8110 Installation and Use (September 2014) - Manual (Page 75)

Functional Description
MVME8100 / MVME8110 Installation and Use (6806800P25G) 75
4.5.1 Real Time Clock
The MVME8100 implements an Real Time Clock (RTC) to maintain seconds, minutes, hours, day, date,
month, and year accurately. It includes a 32.768 KHZ crystal, DS1337 RTC, and back up power. For the ENP1
version of the MVME8100 / MVME8110, a battery is used for the RTC back up power. For the ENP4 version,
a 3.3V regulator powered from the VME backplane +5V_STDBY voltage is used for back up power. The
DS1337 has an interrupt output (INTA) which can be programmed to assert a processor IRQ on a
time/day/date match. The DS1337 also has a 32.768 KHz clock output (SQW) which is used to drive the
P5020 / P5010 RTC input signal.
The RTC internal oscillator has been disabled before the board was shipped from the factory. Use the
following process to turn on the RTC oscillator from Uboot:
MVME8100 => i2c mm 0x68 e.1
0000000e: 98 ? 18
0000000f: 80 ? n
To set the date, use the following uboot command:
MVME8100 =>date [MMDDhhmm[[CC]YY][.ss]]
4.5.2 P5020/ P5010 Internal Timers
The P5020/ P5010 provides a total of eight global timers; it is divided into two groups, group A and group
B. Each group has four timers. Each timer has four individual configuration register. However, these two
groups of timers cannot be cascaded together.
4.5.3 Watchdog Timers
The CPLD has two watchdogs timers, the Initial Hardware Watchdog (IWD) and the OS Watchdog (OSWD).
The Initial Hardware Watchdog is used to guard loading of U-Boot and to prevent board hanging up. U-Boot
has to service IWD before timeout, or IWD will request Power-On Reset. Following a board reset, the board
will try to boot from the U-Boot Flash selected by the configuration switches. If IWD is not serviced in time
by U-Boot, then following the IWD reset, the board will attempt to boot from the alternate SPI1 U-Boot Flash
device.