Optional Sram Battery Backup - Motorola MVME167 Series Installation Manual

Board Level Hardware Description

Optional SRAM Battery Backup

2
2-14
SRAM battery backup is optionally available on the MVME167, but
only as a factory build and only by special request. (Contact your local
Motorola sales office for details.) The battery backup function is
provided by a Dallas DS1210S nonvolatile controller chip and a
Sanyo CR2430 battery.
The onboard power source is a Sanyo CR2430 battery which is
socketed for easy removal and replacement. A small capacitor is
provided to allow the battery to be quickly replaced without data
loss (i.e., the battery must be replaced within 30 seconds).
If your MVME167 is equipped with SRAM battery backup; when
the main board power fails, the DS1210S selects the battery as the
power source.
Each time the board is powered, the DS1210S checks the power
source, allowing software to provide an early warning to avoid
data loss:
If the voltage of the backup source is less than two volts, the
second memory access cycle is blocked.
Because the DS1210S may block the second access, the
software should do at least two accesses before relying on the
data.
With the optional battery backup, the MVME167 provides jumpers
(on Optional SRAM Backup Power Source Select Header J8 on page
3-12) that allow the power source of the DS1210S to be connected to
the VMEbus +5 V STDBY pin or to the onboard battery.