Chapter 2 Processor Pcb; Processor Pcb - NEC Advanced Personal Computer System Reference Manual

Chapter 2
Processor PCB
The Processor PCB (G9PFBU) fits vertically in the Main Unit and is 11 inches long
by 9Y2 inches high (see Figure 2-1). It is composed of four sandwiched layers,
including the signal, ground, and dc-power internal planes. It plugs into the third
slot of the card cage with a IOO-contact edge connector on the bottom of the PCB.
INTR
DMA
CO'lTROLLER
8086
PROCESSOR
RO:vI
CMOS
BATTERY·
BACKED
MEMORY
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Figure 2-1 Processor PCB
BATTERY POWER
SLPPLY CO'l'lECTOR
PARALLEL PRI"fI lOR
I'ITERF,CE
(O'l'lECTOR
RED LED
KEYBOARD
INTERFACE
COI\I\ECTOR
GREEN LED
11
in.
As shown in Figure 2-1, three cable connectors are on the Processor PCB; two are
26-pin connectors and the third is a 2-pin header connector. The Keyboard interface
uses one of the 26-pin connectors, while the other connector provides a parallel
printer (or other such device) interface. Battery power is supplied by the 2-pin
connector.
2-1