vt82c42 ETC-unknow, vt82c42 Datasheet - Page 8

• Manufacturer Part Number: vt82c42
• Description: Vt82c42 Keyboard Controller
• Manufacturer: ETC-unknow

6. VT82C42 Signal Description
Table 4. Signal Description for VT82C42
1. Description for Table 4
RESET# is active low and is only an input pin. VT82C42 requires 10 clocks before RESET# goes to high to
have the chip go to a known state.
Pins WR#, RD#, CS# and A
recognised by the VT82C42.
D
host, write cycle data should cover all the WR# CS# A
VT82C42, the D
cycle after the command is deasserted.
TEST0,TEST1 are input only pins. TEST0 is expected to connect to KBCLK no matter what mode the
VT82C42 is in. TEST1 is expected to connect to KBDATA when in AT-mode, and is expected to connect to
MSCLK when in PS/2 mode. They have a 50K ohm pull up internally.
TH_PROG
0
XTAL 1,
TH_SSPP
RESET#
TEST 0,
XTAL 2
Symbol
TEST 1
TL_EA
-d
P
P
P
P
(BUS)
TH_SS
SYNC
D
WR#
GND
RD#
V
CS#
10
20
14
16
NC
A
7
0
CC
-D
-P
-P
-P
-P
0
are two-way pins, each having 4mA TTL compatible output driving. When D
13
27
15
17
7
VIA Technologies, Inc.
40-Pin
31, 32
33, 34
12-19
27-30
21-24
35-38
10
39
11
40
20
25
26
0
8
6
9
1
2
3
5
7
4
-D
7
is available as long as the RD#=0 CS#=0 command is asserted and is held one clock
1, 13, 23,
44-Pin
35, 36
37, 38
14-20
30-33
24-27
39-42
o
11
10
43
28
29
12
34
44
22
are all input only pins and must activate for at least one clock cycle width to be
9
7
2
3
4
6
8
5
Type
I/O
I/O
I/O
O
O
I
I
I
I
I
I
I
I
I
I
I
Pullup open drain port. Writing a '1' to these ports tri-states the
Pullup open drain port. Writing a '1' to these ports tri-states the
Act as data input or data output.
ports. Act as input 'high' simultaneously if no outside 'low'
connection. Writing a '0' to these ports results in generating a low
on the port.
Output Port 20 - Output Port 23
Output Port 24 - Output Port 27
ports. Act as input 'high' simultaneously if no outside 'low'
connection. Writing a '0' to these ports results in generating a low
on the port.
Input port 16, Input port 17
Act as a write signal.
Act as a read signal.
Chip select of this chip.
Command/Data select when RD# or WR# is active.
Act as Keyboard clock input in both AT mode & PS2 mode
Act as Keyboard Data input in AT mode. Act as Mouse Clock
input in PS2 mode.
Act as clock input to the chips. Can be connected to LC circuit or
a single clock source (X2).
Tie to VCC
Tie to ground.
Internal state synchronous output.
No connection.
A low in this pin reset the chip to a known state.
Power supply of 4.5 to 5.5v.
Ground.
-6-
0
command width. When the D
Name and Function
0
-D
0
-D
7
7
is provided by the
is provided by the
VT82C42