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+5VDC
ADDRESS BUS
DATA BUS
CONTROL SIGNALS
UP TO 4K
PROMIROMI
EPROM
Z-80
MICRO-
4K DYNAMIC
PROCESSOR
RAM
I/O PORT
D
SS
A
19-MHzXTAL
D RE
OSCILLATOR
DECODE
USART
Z80 -PIO
Z80-CTC
I
SERIAL PARALLEL CTC
I/O 110 110
EXTERNAL
PORT SELECTS
Fig. 17-2. Z-80 MCBTM functional block diagram.
addressing range of the Z-80 by slight modifications to the MCB
board. The MCB uses 4K bytes of dynamic RAM in an eight-chip
4K x 1 configuration. At least part of the possible 4K bytes of
ROM in the MCB will probably be one of the versions of the Zilog
monitor. The remaining area available for read-only memory can
OOOOH
OFFFH
1O00H
1FFFH
2000 H
Fig. 17-3. Z-80 MCBTM nominal
memory mapping.
FFFFH
4'K BYTES PROM,
ROM, EPROM
4 K BYTES RAM
56K BYTES
I/
UNUSED
be used for EPROM (erasable programmable read -only memory) or
ROM (read -only memory ). As EPROMs require +5V, -5V, and
+12 VDC, these three voltages must, of course , be externally sup-
plied to the MCB when EPROMS are used. EPROM use also re-
quires minor modifications to the MCB.
249
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