ZiLOG Z80 Handbook page 243

board provides control of up to four floppy-disc drives. The board
provides CRC parity generation and checking and full-status reading
and control under CPU software control. An extra bidirectional 8-bit
PIO port is provided with the addition of this board. The 2K and
4K versions of the MCB system monitor must be used when the Z-80
MDC board is added to provide software for the disc I/O operations.
The MDC is fully compatible with the MCB board and requires only
a 5-VDC supply.
A Z-80 RMB, or RAM Memory Board, is another module in this
series. Additional dynamic RAM storage of 16K bytes is provided
with the RMB board. The RMB board is fully compatible with the
MCB and MDC boards and requires only a 5-VDC supply.
Other modules in this series include a VDB, or Video Interface
Card, PROM memory boards, serial and parallel I/O boards, PROM
or EPROM programmer boards, wire-wrap boards, extender boards,
and a standard card cage that will hold up to nine standard modules.
A complete microcomputer system, the Z-80 MCSTM, is also avail-
able from Zilog. The MCS uses the MCB and MDC and provides
dual floppy discs, power supplies, card cage, and chassis.
MCB MONITOR
A description of the 1K version of the Z-80 MCB PROMT M moni-
tor is provided below . The word monitor as applied to microcom-
puter systems essentially means "debugging program " in the smaller
versions , as the program offers a set of debugging commands that
will display the register contents ; memory contents; alter register or
memory with given data ; save to paper tape and load memory from
paper tape; and control program execution while debugging. The
monitor for the MCB is discussed , not so much to provide a detailed
example of this support program , but as an example of the capabili-
ties of an on - board monitor of this kind.
The commands in the 1K MCB monitor are as shown in Table
17-1. "AAAA" stands for an address value , " NN" stands for a number
Table 17-1. MCB 1K Monitor Commands
Sequence
Command
1
DISPLAY AAAA NN CR
2
SET AAAA DD DD DD DD ... DD CR
3
REGISTER RR (blank)
4 BREAK AAA {N} CR
5
JUMP AAAA CR
6
GO CR
7 PUNCH AAAA AAAA CR
8 LOAD CR
252