ZiLOG Z80 Handbook page 247

HARDWARE MODULES
H
PROCESSOR
MODULE
Z-80, 3K ROM. I K RAM
16K RAM
MEMORY
'OPTIONAL)
ADDITIONAL
16 K RAM MEMORY
REAL-TIME
STORAGE
MODULE
BREAKPOINT
BOARD
FLOPPY-DISC
CONTROLLER
BOARD
IN-CIRCUIT
EMULATOR
BOARD
(OPTIONAL'
PARALLEL I/O
BOARD
F-0------"
USER
HARDWARE
Fig. 17 -5. Zilog Z-80TM development system.
System memory consists of one 16K byte memory module made
up of dynamic RAM. Memory is expandable to 60K bytes of user
memory (4K of addresses are utilized by the Processor Module).
The additional memory below and beyond the 4K used in the pro-
cessor may be in either Monitor Mode or User Mode. In User Mode,
the entire set of additional memory is dedicated to the user's soft-
ware; the user has control over system peripherals and CPU. In the
Monitor Mode, this memory serves as main memory for editing and
assembling.
The Real-Time Storage Module Board contains a 256 by 32
"storage array." The storage array essentially stores events in the
array as they occur on a rolling basis. The user may specify the kind
of events to be recorded under control of the debug software, and
may specify combinations of memory reads or writes, and I/O reads
or writes. As each event occurs during user program execution, the
state of the address bus, data bus, and control bus are stored in the
next location of the 256 places in the array. When the system returns
to Monitor Mode from User Mode, the array may be interpreted and
printed to enable the user to analyze the last events that occurred.
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