The Model 412C System Memory Module
plugs directly into the slot provided for the Traffic
PROM Module in any Model 170 Controller which meets
the State of California TSCE Specification.
General:
The Module is fully buffered on sixteen address and eight
data lines. It provides various jumper selectable configurations
of SRAM (Static Random Access Memory), EPROM (Electrically
Programmable Read Only Memory), and NOVRAM (Nonvolatile SRAM).
The Module is mounted through the front panel of and addressable
from the 170 Controller; and includes two eight position slide
switches, a Write Protect circuit to protect all RAM contents
during power failures, a Real Time Clock Adjuster (RTCA) with
stable master clock, an on-board +12 vdc to +5 vdc converter
power supply, and a voltage sense/battery switch-over circuit.
Memory :
The 412 C System Memory Module incorporates four, twenty-eight
pin sockets to accommodate a variety of memory chip configurations.
The most common maximum configuration consists of 32k of EPROM
and 20K of SRAM. The minimum configuration would consist of
8K of EPROM and no SRAM (the 170 Controller contains 2K of
SRAM). During a power failure the contents of SRAM are protected
from corruption by a Write Protect circuit that monitors the
DC voltage of the Module.
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