1 PB14/IRQ6 I Input of interrupt fromIC506
2 PB15/IRQ7 I Input of interrupt fromIC804
3 VSS – Digital ground
4-11 AD0-7 I/O Data bus AD0-7
12 VSS – Digital ground
13, 14 AD8, 9 I/O Data bus AD8,9
15 VCC – Digital power supply
16-21 AD10-15 I/O Data bus AD10-15
22 VSS – Digital ground
23-30 A0-7 O Addres bus A0-7
31 VSS – Digital ground
32-39 A8-15 O Addres bus A8-15
40 VSS – Digital ground
41, 42 A16, 17 O Addres bus A16,17
43 VCC – Digital power supply
44-47 A18-21 O Addres bus A18-21
48 CS0 O Chip select signal for external ROM(ICS803)
49 CS1 O Chip select signal for external ROM(IC802)
50 CS2 – Not used
51 CS3 – Not used
52 VSS – Digital ground
53 PA0/CS4 O Reset signal for IC101,209
54 PA1/CS5 O Output of reset signal
55 PA2/CS6 O Output of chip select signal to IC804
56 WAIT I Input of wait signal
57 WRL/WR O Output of write signal
58 WRH/LBS – Not used
59 RD O Output of read signal
60 PA7/BACK O Output of reset signal to IC508
61 VSS – Digital ground
62 PA8/BREQ O Output of reset signal to IC101
63 PA9 O Output of reset signal to IC506
64 PA10 O Output of A mute signal
65 PA11 O Output of MA mute signal
66 IRQ0 I Input of interrupt fromIC203
67 IRQ1 I Input of DMA request from IC203
68 IRQ2 I Input of V SYNC(FID) interrupt signal
69 IRQ3 I Input of interrupt from IC804
70 VCC – Digital power supply
71 CK O Output of internal clock
72 VSS – Digital ground
73 EXTAL – 20MHz crystal connection pin
74 XTAL – 20MHz crystal connection pin
75 VCC – Digital power supply
76 NMI I/O Hyper terminal pin
77 VCC (Vpp) – Digital power supply
78 WDTOVF – Not used
79 RES I Input of reset signal
80 MD0 I Input of mode select0 (fixed to 1)
81 MD1 I Input of mode select1 (fixed to 0)
82 MD2 I Input of mode select2 (fixed to 0)
83, 84 VCC – Digital power supply
85 AVCC – Analog power supply
86 AVREF – Reference power supply
87 PC0/AN0 I/O Set of mode 1
88 PC1/AN1 I/O Set of mode 2
89 PC2/AN2 I/O Set of mode 3
90 PC3/AN3 I/O Set of mode 4
91 AVSS – Analog ground
92 PC4/AN4 I/O Set of mode 5
93 PC5/AN5 I/O Set of mode 6
94 PC6/AN6 – Not used
95 PC7/AN7 – Not used
96 VSS – Digital ground
97 PB0 – HFG
98 PB1 O Output of reset signal for IC806
99 VCC – Digital power supply
100 PB2 – Not used
5-2. SYSTEM CONTROL PIN FUNCTION (IC805 on MB-84 Board (13/14))
Pin No. Pin Name I/O Function
Pin No. Pin Name I/O Function
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