Motorola 700/800-Series User Manual

Page of 153
Functional Description
1-21
1
EPROM and Flash Memory
The MVME162LX may be ordered with 2MB of Flash memory and 
two EPROM sockets ready for the installation of the EPROMs, 
which may be ordered separately. Flash memory is a single Intel 
28F016SA device organized in a 2Mbit x 8 configuration. The 
EPROM locations are standard JEDEC 32-pin DIP sockets that 
accommodate three jumper-selectable densities (256 Kbit x 8; 
512 Kbit x 8, the factory default; 1 Mbit x8). A jumper setting (GPI3, 
pins 7-8 on J21), allows reset code to be fetched either from Flash 
memory (GPI3 installed) or from EPROMs (GPI3 removed).
Battery Backed Up RAM and Clock
An M48T58 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 M48T58 is an 8 
bit device, the interface provided by the MC2chip supports 
8-, 16-, and 32-bit accesses to the M48T58. Refer to the MC2chip in 
the MVME162LX Embedded Controller ProgrammerÕs Reference Guide 
and to the M48T58 data sheet for detailed programming and 
battery life information. 
VMEbus Interface and VMEchip2
The optional VMEchip2 provides the local-bus-to-VMEbus 
interface, the VMEbus-to-local-bus interface, and the DMA 
controller functions of the local VMEbus. The VMEchip2 also 
provides the VMEbus system controller functions. Refer to the 
VMEchip2 description in the MVME162LX Embedded Controller 
ProgrammerÕs Reference Guide
 for detailed programming 
information.