Sega Mega-CD - Page 65

MAIN
BOARD
I C 1
1/3
t:' :.-N<> I
l.l"fo~
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.1 N/C
35
o,
2
· OTACK
36
AS
3
BGACK
37
LOS
4
BR
38
BG
HD68HCOOO
5
CLK
39
Vee
6
HALT
40
Vss
r
7
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VMA 41 RES
o.
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8 E
42
VPA
9
BEAR
43
I
IPL2
o,
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10 N/C
44
IPLo
Do
11 FC
2
45 FC,
12 FC
0
46
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N/C
LOS
13
A, 47
A2
14
AJ
48
As
RJW
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BG Ou
15
A•
49
As
16
A6
50
A,o
BGACK
Vn
BP.
Au
Vee An
17
A7
51 A,
AI•
18 Ag 52
Al2
19
N/C
53
A,s
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Vee
HALT A1o
RES Au
20
A,.
54
A,s
21
A,6
55
Vee
VMA
Au
A"
Au
22
A17
56
Vss
Au
23
A19
57
A23
24
A2o
58
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IPLJ
Au
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Au
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25
A21
59
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26
A22
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27
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61
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28
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62
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29
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63
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30
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64
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31
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65 R/W
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32
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66
IPL
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33
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67
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Address Bus
A,
-A23
:±l1J
High
Yes
Yes
Data Bus
Do
-D,s
A.1J/:±l1J High
Yes
Yes
Address Strobe
AS
:±l1J
Low
Yes
No
Read/Write
R/W
:±l1J Read- High
Yes
No
Write- Low
1 Upper and Lower Data Strobes
UDS, LOS
:±l1J
Low
Yes
No
Data Transfer Acknowledge
DTACK
A.1J
Low
No
No
Bus Request
BR
A.1J
Low
No
No
Bus Grant
BG
:±l1J
Low
No
No
Bus Grant Acknowledge
BGACK
A.1J
Low
No
No
Interrupt Priority Level
IP~ ,IPL
1
•
IPL1
A.1J
Low
No
No
Bus Error
BERR
A.1J
Low
No
No
Reset
RES
},:1),. :±l1J
Low
No·
No·
Halt
HALT
A.1J,. :±::n
Low
No·
No·
Enable
E
:±::n
High
No
No
Valid Memory Address
VMA
:±:1J
Low
Yes
No
Valid Peripheral Address
VPA
A.1J
Low
No
No
Function Code Output
FCo.FC,. F~
:±l1J
High
Yes
No
Clock
CLK
A.1J
High
No
No
Power Input
Vee
A.1J
-
-
-
Ground
Vss
A.1J
-
-
-