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MSX Expansion

49 47 45   5 3 1
+---------//-----+
| H H H  //H H H |
| ======//====== |
| H H H//  H H H |
+-----//---------+
 50 48 46  6 4 2

UNKNOWN (at the Computer)

50 PIN ?? at the Computer.

Pin Name Dir Description
1 /CS1 --> Memory Read in addresses 4000-7FFF
2 /CS2 --> Memory Read in addresses 8000-BFFF
3 /CS12 --> Memory Read in addresses 4000-BFFF
4 /SLTSL --> Low when Slot 2 (cartridge slot) is selected
5 n/c - Not connected.
6 /RFSH --> Refresh signal from CPU
7 /WAIT <-- OC, Tells CPU to wait. Refresh signal is not maintained
8 /INT <-- OC, Requests a interrupt to CPU (call to addr 38h)
9 /M1 --> CPU fetches first part of instruction from memory.
10 /BUSDIR <-- NC, was used to control the data direction.
11 /IORQ --> I/O request signal. (Address=Port)
12 /MREQ --> Memory request signal. (Address=Address)
13 /WR --> Write signal (strobe)
14 /RD --> Read signal (strobe)
15 /RESET <-- Reset
16 n/c - Not connected.
17 A0 --> Address 0
18 A1 --> Address 1
19 A2 --> Address 2
20 A3 --> Address 3
21 A4 --> Address 4
22 A5 --> Address 5
23 A6 --> Address 6
24 A7 --> Address 7
25 A8 --> Address 8
26 A9 --> Address 9
27 A10 --> Address 10
28 A11 --> Address 11
29 A12 --> Address 12
30 A13 --> Address 13
31 A14 --> Address 14
32 A15 --> Address 15
33 D0 <-> Data 0
34 D1 <-> Data 1
35 D2 <-> Data 2
36 D3 <-> Data 3
37 D4 <-> Data 4
38 D5 <-> Data 5
39 D6 <-> Data 6
40 D7 <-> Data 7
41 GND --- Ground
42 CLOCK --> CPU clock, 3.579 MHz
43 GND --- Ground
44 SW1 - NC, Insert/remove detection for protection
45 +5V --> +5 VDC (300mA max /slot)
46 SW2 - NC, Insert/remove detection for protection
47 +5V --> +5 VDC (300mA max /slot)
48 +12V --> +12 VDC (50mA max /slot)
49 SOUNDIN <-- Sound input (-5dBm)
50 -12V --> -12 VDC (50mA max /slot)

Note: Direction is Computer relative Peripheral.

Contributor: Joakim Ögren
Source: Mayer's SV738 X'press I/O map

Copyright © The Hardware Book Team 1996-2004.
May be copied and redistributed, partially or in whole, as appropriate.
Document last modified: 2002-01-10