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8 CPU circuit pack
Central processor unit LED display
The CPU circuit pack contains a seven–segment display Light Emitting
Diode (LED) that provides a visual display of error control status. Five
hardware status lines are decoded to display CPU fault conditions. The
display also contains a decimal point feature that provides a visual display of
the CPU clock. See Table 2–1.
Output to the display must occur within 0.5 seconds for the display to
remain valid. This time frame is compatible with the 0.5 second status
request time interval of the error control circuit pack. The data byte and
hardware status lines are decoded by an Erasable Programmable Read Only
Memory (EPROM). Output conditions may appear as shown in Table 2–1.
There are various option settings on this circuit pack. See Table 2–1. Figure
2–2 shows the option locations and circuit pack layout.
Replacing CPU circuit pack
To replace the CPU circuit pack, use the following procedure.
297-1001-536 Standard 01.03 August 1996
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