MAX7359 Maxim, MAX7359 Datasheet - Page 6

• Manufacturer Part Number: MAX7359
• Description: The MAX7359 I²C interfaced peripheral provides microprocessors with management of up to 64 key switches
• Manufacturer: Maxim

2-Wire Interfaced Low-EMI
Key Switch Controller/GPO
The MAX7359 is a microprocessor peripheral low-noise
key-switch controller that monitors up to 64 key switches
with optional autorepeat, and key events are presented
in a 16-byte FIFO. Key-switch functionality can be traded
to provide up to six open-drain logic outputs.
The MAX7359 features an automatic sleep mode and
automatic wakeup that further reduce supply current con-
sumption. The MAX7359 can be configured to enter sleep
mode after a programmable time following a key event.
The FIFO content is maintained during sleep mode and
can be read in sleep mode. The MAX7359 does not enter
autosleep when a key is held down. The autowake feature
takes the MAX7359 out of sleep mode following a key-
press event. Autosleep and autowake can be disabled.
6
TQFN
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
—
1
2
3
4
5
6
7
8
9
_______________________________________________________________________________________
PIN
C2, C3
WLP
C5
C4
D5
D4
D3
D2
D1
C1
A1
A2
A3
B3
A4
A5
B5
B4
E5
E4
E3
E2
E1
B2
B1
—
COL3/PORT3
COL4/PORT4
COL6/PORT6
COL5/PORT5
COL2/PORT2
COL7/PORT7
NAME
ROW2
ROW3
ROW4
ROW5
ROW6
ROW7
ROW0
ROW1
COL1
COL0
GND
Detailed Description
SDA
N.C.
AD0
SCL
V
I.C.
INT
EP
CC
Row Input from Key Matrix. Leave ROW2 unconnected or connect to GND if unused.
Row Input from Key Matrix. Leave ROW3 unconnected or connect to GND if unused.
Column Output to Key Matrix or GPO. Leave COL3/PORT3 unconnected if unused.
Column Output to Key Matrix or GPO. Leave COL4/PORT4 unconnected if unused.
Row Input from Key Matrix. Leave ROW4 unconnected or connect to GND if unused.
Row Input from Key Matrix. Leave ROW5 unconnected or connect to GND if unused.
Row Input from Key Matrix. Leave ROW6 unconnected or connect to GND if unused.
Row Input from Key Matrix. Leave ROW7 unconnected or connect to GND if unused.
Column Output to Key Matrix or GPO. Leave COL6/PORT6 unconnected if unused.
Column Output to Key Matrix or GPO. Leave COL5/PORT5 unconnected if unused.
Column Output to Key Matrix or GPO. Leave COL2/PORT2 unconnected if unused.
Column Output to Key Matrix. Leave COL1 unconnected if unused.
Column Output to Key Matrix. Leave COL0 unconnected if unused.
Internally Connected. Connect to GND for normal operation.
Ground
Adddress Input. ADO selects up to four device slave addresses (Table 10).
I
I
Active-Low Interrupt Output. INT is open drain.
Positive Supply Voltage. Bypass V
No Connection. Not internally connected.
Column Output to Key Matrix or GPO. Leave COL7/PORT7 unconnected is unused.
Row Input from Key Matrix. Leave ROW0 unconnected or connect to GND if unused.
Row Input from Key Matrix. Leave ROW1 unconnected or connect to GND if unused.
Exposed Pad (TQFN only). EP internally is connected to GND. Connect EP to a ground plane
to increase thermal performance.
2
2
C-Compatible, Serial-Data I/O
C-Compatible, Serial-Clock Input
Interrupt requests can be configured to be issued on a
programmable number of FIFO entries, or can be set
to a period of time to prevent overloading the micro-
processor with too many interrupts. The key-switch sta-
tus can be checked at any time by reading the
key-switch FIFO. A 1-byte read access returns both the
next key-event in the FIFO (if there is one) and the
FIFO status, so it is easy to operate the MAX7359 by
polling. If the INT pin is not required, it can be config-
ured as an open-drain general-purpose output (GPO)
capable of driving an LED.
If the application requires fewer keys to be scanned, up
to six of the key-switch outputs can be configured as
open-drain GPOs capable of driving LEDs. For each
key-switch output used as a GPO, the number of key
switches that can be scanned is reduced by eight.
CC
to GND with a 0.047µF or higher ceramic capacitor.
FUNCTION
Pin Description