Information Technology Reference
In-Depth Information
B
VESA VL-Local Bus
Table B.1 lists the pin connections for the 32-bit VL-local bus and it shows that, in addition
to the standard ISA connector, there are two sides of connections, the A and the B side. Each
side has 58 connections giving a total of 116 connections. It has a full 32-bit data and address
bus. The 32 data lines are labelled DAT00-DAT31 and 32 address lines are labelled from
ADR00-ADR31. Note that although the data and address lines are contained within the extra
VL-local bus extension, some of the standard ISA lines are used, such as the IRQ lines.
The VL-local bus uses a standard ISA connector and an extra connector to tap into the
32-bit data and address busses. Table B.1 lists the additional 32-bit VESA VL-local bus con-
nections. It has a 32-bit data bus (D0-D31) and a full 32-bit address bus (A0-A31). The VL-
Local bus is an extension to the standard ISA bus and can thus use the interrupt lines on the
ISA bus con
nec
tor, that
is
, IRQ3-IRQ7 and IRQ10-IRQ14. It also has the memory address-
ing lines (M/ IO and R/ W).
Table B.1
32-bit VESA VL-local bus connections
Pin
Side-A
Side-B
Pin
Side-A
Side-B
1
D0
D1
30
A17
A16
2
D2
D3
31
A15
A14
3
D4
GND
32
VCC
A12
4
D6
D5
33
A13
A10
5
D8
D7
34
A11
A8
6
GND
D9
35
A9
GND
7
D10
D11
36
A7
A6
8
D12
D13
37
A5
A4
9
VCC
D15
38
GND
WB
ACK
10
D14
GND
39
A3
BE0
11
D16
D17
40
A2
VCC
12
D18
VCC
41
NC
BE1
13
D20
D19
42
RE
SE
T
BE2
14
GND
D21
43
D/C
GND
15
D22
D23
44
M/IO
BE3
16
D24
D25
45
W/R
ADS
17
D26
GND
46
KEY
KEY
18
D28
D27
47
KEY
KEY
19
D30
D29
48
RDYRTN
LRDY
20
VCC
D31
49
GND
LDEV
21
A31
A30
50
IRQ9
LREQ
22
GND
A28
51
BRDY
GND
23
A29
A26
52
BLAST
LGNT
24
A27
GND
53
IDO VCC
25
A25
A24
54
ID1
ID2
26
A23
A22
55
GND
ID3
27
A21
VCC
56
LCLK
ID4
28
A19
A20
57
VCC
NC
29
GND
A18
58
LBS16
LEADS
