2 pin listing description – Rainbow Electronics AT42QT4120 User Manual
Page 2
2
9506AS–AT42–10/08
AT42QT4120
1.2
Pin Listing Description
I
Input only
I/O
Input and output
O
Output only, push-pull
X
Clock resonator
OD
Open drain output
P
Ground or power
Table 1-1.
Pin Listing
Pin
Name
Type
Comments
If Unused, connect To...
1
N/C
O
Not connected
Leave open
2
CHANGE
OD
State change notification
Leave open
3
Vss
P
Supply ground
–
4
Vdd
P
Power
–
5
Vss
P
Supply ground
–
6
Vdd
P
Power
–
7
N/C
O
Not connected
Leave open
8
N/C
O
Not connected
Leave open
9
Vss
P
Supply ground
–
10
VREF
I
Supply ground
–
11
SMP
O
Sample output
–
12
X0
O
X matrix drive line
Leave open
13
X1
O
X matrix drive line
Leave open
14
X2
O
X matrix drive line
Leave open
15
X3
O
X matrix drive line
Leave open
16
N/C
O
Not connected
Leave open
17
N/C
O
Not connected
Leave open
18
Vdd
P
Power
–
19
Vdd
P
Power
–
20
Vdd
P
Power
–
21
Vss
P
Supply ground
–
22
A0
I
I
2
C-compatible address select
–
23
Y0B
I/O
Y line connection
Leave open
24
Y1B
I/O
Y line connection
Leave open
25
Y2B
I/O
Y line connection
Leave open
26
N/C
O
Not connected
Leave open
27
SDA
OD
Serial Interface Data
–
28
SCL
OD
Serial Interface Clock
–
29
RST
I
Reset low; has internal 30k - 60k pull-up
Leave open or Vdd
30
Y0A
O
Y line connection
Leave open
31
Y1A
O
Y line connection
Leave open
32
Y2A
O
Y line connection
Leave open