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M/.3500 – Sharp MZ-3500 User Manual

Page 19

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M/.3500

Pm No

Polarity

Signal Name

IN/OUT

Function

57

SYSR

IN

System reset signal.

Used to reset I/O port in the MMR.

(System Reset)

58

FD3

IN

Input from the sytem assignment dip switch.

•$ee the dip switch description, provided separately.

59

COAB

IN

Shared RAM select signal.

Address of the shared RAM is i?F800-#FFFF

for

the main

CPU

(Common RAM Address)

60

R01B

OUT

Select signal for 8KB area allocated to slot 1.

Valid when SD2 is active (ROM based BASIC) and SD3

(RAM based BASIC)

(ROM 1)

61

GND

IN

Ground

62

Vcc

IN

5V supply

63

64

R02B

R03B

OUT

Select signal for 8KB area allocated to slot 2 or 3.

Valid when SD2 is active (ROM based BASIC) and SD3

(RAM based BASIC).

(ROM2, 3)

65

RDB

IN

Read signal from the main CPU.

(Read)

66

CLK

EAIT signal generation clocit.

(Clock)

67

R04B

OUT

Select signal for 8KB area allocated to slot 4.

Valid when SD2 or SD3 (RAM based BASIC) are active.

(ROM 4)

68

MPX

OUT

RAS/CAS address switching signal for the main CPU DRAM.
High: Row address Low: Column address

(Multiplex)

69

GND

IN

Ground

70

CASB

OUT

CAS (Column Address) signal for the main CPU 64K DRAM.

•Refresh for the RAM only.

(Column Address Select Buffer)

71

GND

IN

Ground

72

INTB

OUT

Interrupt signal to the main CPU.

(Interrupt)

73

Not used