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M 7,3500
Pin No.
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
Polarity
Signal Name
SYSR
FD3
COAB
RO1B
GND
Vcc
RO2B
RÖ3B
'ROB
CLK
RO4B
MPX
GND
CASB
GND
INTB
IN/OUT
IN
IN
IN
OUT
IN
IN
OUT
IN
OUT
OUT
IN
OUT
IN
OUT
Function
System reset Signal.
Used to reset I/O port in the MMR.
(System Reset)
Input from the sytem assignment dip switch.
'See the dip switch description, provided separately.
Shared RAM Select Signal.
Address of the shared RAM is *F800-#FFFF for the main CPU
(Common RAM Address)
Select Signal for 8KB area allocated to slot 1.
Valid when SD2 is active (ROM based BASIC) and SD3 (RAM based BASIC).
(ROM 1)
Ground
5V supply
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)
Read signal from the main CPU.
(Read)
EAIT signal generation Clock.
(Clock)
Select signal for 8KB area allocated to slot 4.
Valid when SD2 or SD3 (RAM based BASIC) are active.
(ROM 4)
RAS/CAS address switching signal for the main CPU DRAM.
High: Row address
Low: Column address
(Multiplex)
Ground
CAS (Column Address) signal for the main CPU 64K DRAM.
•Refresh for the RAM only.
(Column Address Select Buffer)
Ground
'
l
h
•
(Interrupt)
Not used
-22-
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