Mz 3500, Main cpu start – Sharp MZ-3500 User Manual

Page 9

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MZ 3500

Operational description

(1)

Upon reset after power on, the main CPU loads the

contents of the initial program loader (IPL) into RAM

starting at address 4000H, during which time reset is

applied to the sub-CPU.

TIMING OF RESET SIGNAL

(

2

)

(3)

The main CPU then terminates resetting the sub CPU

and starts the sub-CPU. At the same time, the ROM

IPL is assigned to the sub-CPU.

The main CPU then send the memory allocation (state)

to SDÌ, and starts to load DOS from the system floppy

disk.

Signal generated from the
CR network and power supply

Output signal from the mam CPU port

MAIN CPU

START

a.

Main CPU reset time

b.

Main CPU IPL load time

Memory Map Data:

1. ROM-B is tested to determine if ROM's are present.

2.

The ROM-IPL functions under control of the main CPU

at first, but later it functions under the sub-CPU after

the IPL program has been loaded in RAM.

3.

RAM-COM is shared by both the main CPU and the sub-

CPU.

INITIALIZE FLOW

„„

t

4. Memories other than described above cannot be accessed

under the SDO state.

5. Bank select, MA0~MA3, is used within the address range

of COOOH-FFFFH.

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