Datasheet

5
9596A–AT42–10/10
AT42QT1070
Table 1-2. Pin Listings (20-pin VQFN)
Pin
Name
(Comms
Mode)
Name
(Standalone
Mode) Type Description
If Unused,
Connect To...
1 KEY4 KEY4 O Key 4 Open
2 KEY3 KEY3 O Key 3 Open
3 KEY2 KEY2 O Key 2 Open
4 KEY1 KEY1 O Key 1 Open
5 KEY0 KEY0 O Key 0 Open
6N/C N/C– Not connected –
7N/C N/C–
Not connected –
8 Vss Vss P Ground –
9Vdd VddPPower –
10 N/C N/C –
Not connected –
11 MODE (Vss) MODE (Vdd) I
Mode selection pin
Comms Mode – connect to Vss
Standalone Mode – connect to Vdd
–
12 SDA OUT0 OD
Comms Mode – I
2
C-compatible data line
Standalone Mode – open drain output for guard
channel
Open
13 RESET
RESET I RESET – has internal pull-up 60 k resistor Open
14
CHANGE OUT4 OD
CHANGE line for controlling the communications
flow
Comms Mode – connect to CHANGE
line
Standalone Mode – connects to output
Open
15 SCL OUT3 OD
Comms Mode – connect to I
2
C-compatible clock
Standalone Mode – connect to output
Open
16 KEY6 OUT2 O/OD
Comms Mode – connect to Key 6
Standalone Mode – connect to output
Open
17 KEY5 OUT1 O/OD
Comms Mode – connect to Key 5
Standalone Mode – connect to output
Open
18 N/C N/C –
Not connected –
19 N/C N/C –
Not connected –
20 N/C N/C –
Not connected –
I Input only
O Output only, push-pull
OD Open drain output
P Ground or power