General-Purpose Timers; Real-Time Clock Battery; Reset Control Logic - Emerson MVME3100 Series Installation And Use Manual

4.11 General-Purpose Timers

There are a total of eight independent, 32-bit timers. Four timers are integrated into the
MPC8540 and four timers are in the PLD. The four MPC8540 timers are clocked by the RTC
input, which is driven by a 1 MHz clock. The clock source for the four timers in the PLD is 25
MHz. Refer to the MPC8540 Reference Manual listed in
additional details and/or programming information.

4.12 Real-time Clock Battery

There is an on-board Renata SMT battery holder on the MVME3100. This SMTU2430-1 holder
allows for quick and easy replacement of a 3V button cell lithium battery (CR2430), which
provides back-up power to the on-board DS1375 RTC. A battery switching circuit provides
automatic switching between the 3.3V and battery voltages. The battery provides backup
power to the RTC for a minimum of one year at nominal temperature.

4.13 Reset Control Logic

The sources of reset on the MVME3100 are the following:
Power-up
Reset switch
Watchdog timer
System Control register bit
VMEbus reset
A board-level hard reset generates a reset for the entire board including the MPC8540, local
PCI/PCI-X buses, Ethernet PHYs, serial ports, Flash devices, and PLD(s). If the MVME3100 is
configured as the VME system controller, the VME bus and local TSi148 reset input are also
reset.
MVME3100 Single Board Computer Installation and Use (6806800M28C)
Functional Description
Appendix B, Related Documentation, for
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