Eprom And Flash Memory; Battery Backed Up Ram And Clock - Motorola MVME162LX 300 Series Installation And Use Manual

Board Level Hardware Description
1

EPROM and Flash Memory

Battery Backed Up RAM and Clock

1-18
When a controller is stored, the battery should be disconnected to prolong
battery life. This is especially important at high ambient temperatures. The
controller is shipped with the batteries disconnected (with VMEbus +5V
standby voltage selected as both primary and secondary power source). If
you intend to use the battery as a power source, whether primary or
secondary, it is necessary to reconfigure the jumpers on J13 before installing
the module.
The power leads from the battery are exposed on the solder side of the board.
The board should not be placed on a conductive surface or stored in a
conductive bag unless the battery is removed.
To remove the battery from the module, carefully pull the battery from the
socket. Before installing a new battery, ensure that the battery pins are clean.
Note the battery polarity and press the battery into the socket. When the
battery is in the socket, no soldering is required.
The MVME162LX Embedded Controller comes with 1 MB of flash
memory and four EPROM sockets ready for the installation of EPROMs,
which may be ordered separately. Flash memory is a single Intel 28F008SA
device organized in a 1Mbit x 8 configuration. The EPROM locations are
standard JEDEC 32-pin DIP sockets accommodating four jumper-selectable
densities (128 Kbit x 8; 256 Kbit X 8; 512 Kbit x 8; 1 Mbit x8). A jumper
setting (GPIO3, pins 7-8 on J11), allows reset code to be fetched either from
flash memory (GPIO3 installed) or from EPROMs (GPIO3 removed).
An MK48T08 RAM and clock chip is used on the MVME162LX. This chip
provides a time-of-day clock, oscillator, crystal, power fail detection,
memory write protection, 8KB of RAM, and a battery in one 28-pin
package. The clock provides seconds, minutes, hours, day, date, month, and
year in BCD 24-hour format. Corrections for 28-, 29- (leap year), and 30-
day months are automatically made. No interrupts are generated by the
clock. Although the MK48T08 is an 8 bit device, the interface provided by
the MCchip supports 8-, 16-, and 32-bit accesses to the MK48T08. Refer to
the MCchip in the MVME162LX Embedded Controller Programmer's
Reference Guide and to the MK48T08 data sheet for additional
programming and battery life information.
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