Rainbow Electronics MAX7360 User Manual

MAX7360

AD0

PORT7
PORT6

PORT0

COL_(8x)

ROW_(8x)

INTK

INTI

SDA

SCL

ROTARY
SWITCH

+14V

8 x 8

TO
FC

+1.8V

19-4566; Rev 0; 4/09

EVALUATION KIT

AVAILABLE

I2C-Interfaced Key-Switch Controller and LED

Driver/GPIOs with Integrated ESD Protection

General Description

The MAX7360 I2C-interfaced peripheral provides micro­processors with management of up to 64 key switches,
with an additional eight LED drivers/GPIOs that feature
constant-current, PWM intensity control, and rotary
switch control options.

The key-switch drivers interface with metallic or resistive
switches with on-resistances up to 5kI. Key inputs
are monitored statically, not dynamically, to ensure
low-EMI operation. The MAX7360 features autosleep
and autowake modes to further minimize the power
consumption of the device. The autosleep feature puts
the device in a low-power state (1FA typ) after a sleep
timeout period. The autowake feature configures the
MAX7360 to return to normal operating mode from sleep
upon a keypress.

The key controller debounces and maintains a FIFO of
keypress and release events (including autorepeat, if
enabled). An interrupt (INTK) output can be configured
to alert keypresses, as they occur, or at maximum rate.

There are eight open-drain I/O ports, which can be used
to drive LEDs. The maximum constant-current level for
each open-drain port is 20mA. The intensity of the LED
on each open-drain port can be individually adjusted
through a 256-step PWM control. An input port pair
(PORT6, PORT7) can be configured to accept 2-bit gray
code inputs from a rotary switch. In addition, if not used
for key-switch control, up to six column pins can be used
as general-purpose open-drain outputs (GPOs) for LED
drive or logic control.

The MAX7360 is offered in a 40-pin (5mm x 5mm) thin
QFN package with an exposed pad, and a small 36-bump
wafer level package (WLP) for cell phones, pocket PCs,
and other portable consumer electronic applications. The
MAX7360 operates over the -40NC to +85NC extended
temperature range.

Applications

Cell Phones

PDAs

Handheld Games

Portable Consumer Electronics

Printers

Instrumentation

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.

_______________________________________________________________ Maxim Integrated Products 1

Features

S Integrated ESD Protection

Q8kV IEC 61000-4-2 Contact Discharge
Q15kV IEC 61000-4-2 Air-Gap Discharge

S +14V Tolerant, Open-Drain I/O Ports Capable of

Constant-Current LED Drive

S Rotary Switch-Capable Input Pair (PORT6, PORT7)
S 256-Step PWM Individual LED Intensity Control
S Individual LED Blink Rates and Common LED

Fade In/Out Rates from 256ms to 4096ms

S FIFO Queues Up to 16 Debounced Key Events
S User-Configurable Key Debounce (9ms to 40ms)
S Keyscan Uses Static Matrix Monitoring for Low

EMI Operation

S +1.62V to +3.6V Operation
S Monitors Up to 64 Keys
S Key-Switch Interrupt (INTK) on Each Debounced

Event/FIFO Level, or End of Definable Time Period

S Port Interrupt (INTI) for Input Ports for Special-Key

Functions

S 400kbps, +5.5V Tolerant 2-Wire Serial Interface

with Selectable Bus Timeout

S Four I

2

C Address Choices

Ordering Information

PART TEMP RANGE PIN-PACKAGE

MAX7360ETL+ -40°C to +85°C 40 TQFN-EP*

MAX7360EWX+** -40°C to +85°C 36 WLP

+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
**Future product—contact factory for availability.

Simplfied Block Diagram

Pin Configurations appear at end of data sheet.

MAX7360

I2C-Interfaced Key-Switch Controller and LED
Driver/GPIOs with Integrated ESD Protection

ABSOLUTE MAXIMUM RATINGS

VCC to GND ............................................................. -0.3V to +4V

COL0–COL7, ROW0–ROW7 to GND ......................-0.3V to +4V

SDA, SCL, AD0, INTI, INTK to GND ........................ -0.3V to +6V

PORT0–PORT7 to GND ......................................... -0.3V to +16V

All Other Pins to GND ................................-0.3V to (VCC + 0.3V)

DC Current on PORT0–PORT7, COL2–COL7 ....................25mA

GND Current .......................................................................80mA

Continuous Power Dissipation (TA = +70NC)

MAX7360

40-Pin TQFN (derate 22.2mW/NC above +70NC).......1777mW

36-Bump WLP (derate 21.7mW/NC above +70NC) .... 1739mW

Junction-to-Case Thermal Resistance (BJC) (Note 1)

40-Pin TQFN .................................................................. 2NC/W

36-Bump WLP ...................................................................N/A

Junction-to-Ambient Thermal Resistance (BJA) (Note 1)

40-Pin TQFN ................................................................ 45NC/W

36-Bump WLP .............................................................46NC/W

Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a single­ layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial.
Note 2: Refer to Pb-free solder-reflow requirements described in J-STD-020, Rev D.1, or any other paste supplier specification.

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these
or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may
affect device reliability.

Operating Temperature Range .......................... -40NC to +85NC

Junction Temperature .....................................................+150NC

Storage Temperature Range ............................ -65NC to +150NC

ESD Protection
Human Body Model (RD = 1.5kI, CS = 100pF)

All Pins .............................................................................Q2kV

IEC61000-4-2 (RD = 330I, CS = 150pF)
Contact Discharge

ROW0–ROW7, COL0–COL7, PORT0–PORT7 to GND ....Q8kV

Air-Gap Discharge
ROW0–ROW7, COL0–COL7, PORT0–PORT7 to GND ..Q15kV
Lead Temperature (soldering, 10s)

40-Pin TQFN ................................................................+300NC

36-Bump WLP ........................................................... (Note 2)

ELECTRICAL CHARACTERISTICS

(VCC = +1.62V to +3.6V, TA = -40NC to +85NC, unless otherwise noted. Typical values are at VCC = +3.3V, TA = +25NC.) (Notes 3, 4)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Operating Supply Voltage V

External Supply Voltage
PORT0–PORT7

Operating Supply Current I

Sleep-Mode Supply Current I
Key-Switch Source Current I
Key-Switch Source Voltage V
Key-Switch Resistance R
Startup Time from Shutdown t

Output Low Voltage
COL2–COL7

Oscillator Frequency (PWM
Clock)

Oscillator Frequency Variation Df

Key-Scan Frequency f

V

CC

PORT_

CC

SL

KEY

KEY

KEY

START

V

OL

f

OSC

OSC

KEY

All key switches open, oscillator running,
COL2–COL7 configured as key switches,
V

_ = V

PORT

N keys pressed

(Note 5) 5 kI

I

SINK

TA = +25NC, VCC = +2.61V 125 128 131

TA = T

TA = +25NC -6 +8.5 %

Derived from oscillator clock 64 kHz

CC

= 10mA 0.5 V

- T

, V

MIN

MAX

P 3.6V 102 164

CC

1.62 3.3 3.6 V

14 V

34 50

FA

34 +

20 x N

1.3 3 FA
20 35 FA

0.43 0.5 V

2 2.4 ms

kHz

2 ______________________________________________________________________________________

I2C-Interfaced Key-Switch Controller and LED

Driver/GPIOs with Integrated ESD Protection

ELECTRICAL CHARACTERISTICS (continued)

(VCC = +1.62V to +3.6V, TA = -40NC to +85NC, unless otherwise noted. Typical values are at VCC = +3.3V, TA = +25NC.) (Notes 3, 4)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

GPIO SPECIFICATIONS

Input High Voltage
PORT0–PORT7

Input Low Voltage
PORT0–PORT7

Input Leakage Current
PORT0–PORT7

Output Low Voltage
PORT0–PORT7

Input Capacitance
PORT0–PORT7

10mA Port Sinking Current
PORT0–PORT7

V

IH

V

IL

VIN P V

I

IN

V

OL

CC

VCC < V

I

VCC = +1.62V to +3.6V, TA = +25NC 8.55 11.52

VCC = +3.3V, VOL = +1V 8.67 9.76 10.51

IN

< 20mA 0.6 V

SINK

0.7 x
V

CC

0.3 x
V

CC

-0.25 +0.25

-1 +5

20 pF

V

V

FA

mA

MAX7360

20mA Port Sinking Current
PORT0–PORT7

Port Sink Current Variation

Output Logic-Low Voltage

INTI, INTK

PWM Frequency f

SERIAL-INTERFACE SPECIFICATIONS

Input High Voltage
SDA, SCL, AD0

Input Low Voltage
SDA, SCL, AD0

Input Leakage Current
SDA, SCL, AD0

Output Low Voltage
SDA

Input Capacitance
SDA, SCL, AD0

I2C TIMING SPECIFICATIONS

SCL Serial-Clock Frequency f

Bus Free Time Between a STOP
and START Condition

Hold Time (Repeated) START
Condition

Repeated START Condition
Setup Time

STOP Condition Setup Time t

PWM

V

C

t

t

HD, STA

t

SU, STA

SU, STO

V

IH

V

IL

I

IN

OL

IN

SCL

BUF

VCC = +1.62V to +3.6V, TA = +25NC 19.40 21.33

VCC = +3.3V, VOL = +1V 19.55 20 20.69

VCC = +3.3V, VOL = +1V, TA = +25NC,
20mA output mode

I

= 10mA 0.6 V

SINK

Derived from oscillator clock 500 Hz

0.7 x
V

VIN P V

CC

VIN > V

CC

I

= 6mA 0.6 V

SINK

Bus timeout disabled 0 400 kHz

-0.25 +0.25

-0.5 +0.5

1.3 Fs

0.6 Fs

0.6 Fs

0.6 Fs

+Q1.5 +Q2.4 %

CC

10 pF

0.3 x

V

CC

mA

V

V

FA

_______________________________________________________________________________________ 3

I2C-Interfaced Key-Switch Controller and LED
Driver/GPIOs with Integrated ESD Protection

ELECTRICAL CHARACTERISTICS (continued)

(VCC = +1.62V to +3.6V, TA = -40NC to +85NC, unless otherwise noted. Typical values are at VCC = +3.3V, TA = +25NC.) (Notes 3, 4)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Data Hold Time t
Data Setup Time t
SCL Clock Low Period t
SCL Clock High Period t

MAX7360

Rise Time of Both SDA and SCL
Signals, Receiving

Fall Time of Both SDA and SCL
Signals, Receiving

Fall Time of SDA Signal,
Transmitting

Pulse Width of Spike Suppressed t

Capacitive Load for Each Bus
Line

Note 3: All parameters are tested at TA = +25NC. Specifications over temperature are guaranteed by design.
Note 4: All digital inputs at VCC or GND.

Note 5: Guaranteed by design.
Note 6: A master device must provide a hold time of at least 300ns for the SDA signal (referred to VIL of the SCL signal) to bridge

the undefined region of SCL’s falling edge.

Note 7: Cb = total capacitance of one bus line in pF. tR and tF measured between +0.8V and +2.1V.
Note 8: I

Note 9: Input filters on the SDA, SCL, and AD0 inputs suppress noise spikes less than 50ns.

P 6mA. Cb = total capacitance of one bus line in pF. tR and tF measured between +0.8V and +2.1V.

SINK

HD, DAT

SU, DAT

LOW

HIGH

t

R

t

F

t

F, TX

SP

C

(Note 6) 0.9 Fs

100 ns

1.3 Fs

0.7 Fs

(Notes 5, 7)

(Notes 5, 7)

(Notes 5, 8)

(Notes 5, 9) 50 ns

(Note 5) 400 pF

b

20 +

0.1C

20 +

0.1C

20 +

0.1C

b

b

b

300 ns

300 ns

250 ns

4 ______________________________________________________________________________________

I2C-Interfaced Key-Switch Controller and LED

SINK CURRENT (mA)

SINK CURRENT (mA)

CONSTANT-CURRENT GPIO OUTPUT

CONSTANT-CURRENT GPIO OUTPUT

CONSTANT-CURRENT GPIO OUTPUT

Driver/GPIOs with Integrated ESD Protection

Typical Operating Characteristics

(VCC = +2.5V, TA = +25NC, unless otherwise noted.)

MAX7360

GPO OUTPUT LOW VOLTAGE

vs. SINK CURRENT (COL2–COL7)

250

VCC = 2.4V

200

150

100

OUTPUT VOLTAGE (mV)

50

0

0 20

TA = +85NC

TA = +25NC

SINK CURRENT (mA)

SUPPLY CURRENT

vs. SUPPLY VOLTAGE

45

AUTOSLEEP = OFF

40

35

30

25

SUPPLY CURRENT (A)

20

15

TA = +25NC

2.0

1.6 3.6
SUPPLY VOLTAGE (V)

TA = +85NC

TA = -40NC

2.4

2.8

TA = -40NC

15105

3.2

GPO OUTPUT LOW VOLTAGE

vs. SINK CURRENT (COL2–COL7)

250

VCC = 3.0V

MAX7360 toc01

200

150

100

OUTPUT VOLTAGE (mV)

50

0

0 20

KEY-SWITCH SOURCE CURRENT

18.4
V

= O

COL0

18.3

MAX7360 toc04

18.2

18.1

18.0

TA = +85NC

17.9

17.8

17.7

17.6

KEY-SWITCH SOURCE CURRENT (A)

17.5

TA = -40NC, +25NC

17.4

1.6 3.63.2

TA = +85°C

TA = +25°C

vs. SUPPLY VOLTAGE

TA = -40NC, +85NC

TA = -40NC

2.42.0

2.8

SUPPLY VOLTAGE (V)

TA = -40°C

15105

TA = +25NC

GPO OUTPUT LOW VOLTAGE

vs. SINK CURRENT (COL2–COL7)

250

VCC = 3.6V

MAX7360 toc02

200

150

100

OUTPUT VOLTAGE (mV)

50

0

0 20

SHUTDOWN SUPPLY CURRENT

3.0

2.5

MAX7360 toc05

2.0

1.5

1.0

SHUTDOWN SUPPLY CURRENT (A)

0.5

0

1.6 3.63.2

TA = +85°C

TA = +25°C

vs. SUPPLY VOLTAGE

TA = -40NC

TA = +25NC

TA = +85NC

2.8

2.42.0

SUPPLY VOLTAGE (V)

MAX7360 toc03

TA = -40°C

15105

MAX7360 toc06

SINK CURRENT vs. OUTPUT VOLTAGE

25

VCC = 2.4V

20

TA = -40NC

15

10

SINK CURRENT (mA)

5

0

TA = +25NC

TA = +85NC

0 3.02.5

OUTPUT VOLTAGE (V)

_______________________________________________________________________________________ 5

SINK CURRENT vs. OUTPUT VOLTAGE

25

VCC = 3.0V

MAX7360 toc07

20

TA = -40NC

15

10

SINK CURRENT (mA)

5

0

1.5 2.01.00.5

TA = +25NC

TA = +85NC

0 3.02.5

1.5 2.01.00.5

OUTPUT VOLTAGE (V)

MAX7360 toc08

SINK CURRENT vs. OUTPUT VOLTAGE

25

VCC = 3.6V

20

TA = -40NC

15

10

SINK CURRENT (mA)

5

0

TA = +25NC

TA = +85NC

0 3.02.5

1.5 2.01.00.5

OUTPUT VOLTAGE (V)

MAX7360 toc09

I2C-Interfaced Key-Switch Controller and LED
Driver/GPIOs with Integrated ESD Protection

Pin Description

PIN

TQFN WLP

1 A6 ROW0 Row Input from Key Matrix. Leave ROW0 unconnected or connect to GND if unused.
2 B6 ROW1 Row Input from Key Matrix. Leave ROW1 unconnected or connect to GND if unused.
3 C4 ROW2 Row Input from Key Matrix. Leave ROW2 unconnected or connect to GND if unused.

MAX7360

4 C6 ROW3 Row Input from Key Matrix. Leave ROW3 unconnected or connect to GND if unused.

5, 15, 25, 35B4, C5, D2,

E4

6 D6 ROW4 Row Input from Key Matrix. Leave ROW4 unconnected or connect to GND if unused.
7 D5 ROW5 Row Input from Key Matrix. Leave ROW5 unconnected or connect to GND if unused.
8 E6 ROW6 Row Input from Key Matrix. Leave ROW6 unconnected or connect to GND if unused.
9 D4 ROW7 Row Input from Key Matrix. Leave ROW7 unconnected or connect to GND if unused.

10, 20, 27,

30, 40

11 F6 COL0 Column Output to Key Matrix. Leave COL0 unconnected if unused.
12 E5 COL1 Column Output to Key Matrix. Leave COL1 unconnected if unused.

13 F5 COL2

14 F4 COL3

16 F3 COL4

17 E3 COL5

18 F2 COL6

19 F1 COL7

21 E2 SDA I2C-Compatible, Serial-Data I/O
22 E1 SCL I2C-Compatible, Serial-Clock Input

23 D3 INTK

C2 N.C. No Connection. Not internally connected. Leave unconnected.

NAME FUNCTION

GND Ground

Column Output to Key Matrix. Leave COL2 unconnected if unused. COL2 can be
configured as a GPO (see Table 9 in the Register Tables section).

Column Output to Key Matrix. Leave COL3 unconnected if unused. COL3 can be
configured as a GPO (see Table 9 in the Register Tables section).

Column Output to Key Matrix. Leave COL4 unconnected if unused. COL4 can be
configured as a GPO (see Table 9 in the Register Tables section).

Column Output to Key Matrix. Leave COL5 unconnected if unused. COL5 can be
configured as a GPO (see Table 9 in the Register Tables section).

Column Output to Key Matrix. Leave COL6 unconnected if unused. COL6 can be
configured as a GPO (see Table 9 in the Register Tables section).

Column Output to Key Matrix. Leave COL7 unconnected if unused. COL7 can be
configured as a GPO (see Table 9 in the Register Tables section).

Active-Low Key-Switch Interrupt Output. INTK is open drain and requires a pullup
resistor.

6 ______________________________________________________________________________________

I2C-Interfaced Key-Switch Controller and LED

Driver/GPIOs with Integrated ESD Protection

Pin Description (continued)

MAX7360

PIN

TQFN WLP

24 D1 INTI Active-Low GPI Interrupt Output. INTI is open drain and requires a pullup resistor.
26 C1 V
28 B1 AD0 Address Input. AD0 selects up to four device slave addresses (Table 3).
29 A1 I.C. Internally Connected. Connect to GND for normal operation.

31 B2 PORT0

32 A2 PORT1

33 B3 PORT2

34 A3 PORT3

36 A4 PORT4

37 C3 PORT5

38 A5 PORT6

39 B5 PORT7

— — EP

NAME FUNCTION

Positive Supply Voltage. Bypass VCC to GND with a 0.1FF or higher ceramic capacitor.

CC

GPIO Port. Open-drain I/O rated at +14V. PORT0 can be configured as a constant­current output.

GPIO Port. Open-drain I/O rated at +14V. PORT1 can be configured as a constant­current output.

GPIO Port. Open-drain I/O rated at +14V. PORT2 can be configured as a constant­current output.

GPIO Port. Open-drain I/O rated at +14V. PORT3 can be configured as a constant­current output.

GPIO Port. Open-drain I/O rated at +14V. PORT4 can be configured as a constant­current output.

GPIO Port. Open-drain I/O rated at +14V. PORT5 can be configured as a constant­current output.

GPIO Port. Open-drain I/O rated at +14V. PORT6 Can be configured as a constant­current output, or a rotary switch input.

GPIO Port. Open-drain I/O rated at +14V. PORT7 can be configured as a constant­current output, or a rotary switch input.

Exposed Pad (TQFN only). EP is internally connected to GND. Connect EP to a ground
plane to increase thermal performance.

_______________________________________________________________________________________ 7

I2C-Interfaced Key-Switch Controller and LED
Driver/GPIOs with Integrated ESD Protection

Functional Block Diagram

PORT0
PORT1
PORT2
PORT3
PORT4
PORT5
PORT6
PORT7

COL0
COL1
COL2*
COL3*
COL4*
COL5*
COL6*
COL7*

ROW0
ROW1
ROW2
ROW3
ROW4
ROW5
ROW6
ROW7

MAX7360

INTI

INTK

SDA

SCL
AD0

MAX7360

I2C

INTERFACE

BUS

TIMEOUT

128kHz

OSCILLATOR

CONTROL

REGISTERS

FIFO

POR

PWM

GPIO

LOGIC

ROTARY

KEY

SCAN

LED ENABLE

GPIO ENABLE

GPIO INPUT

COLUMN ENABLE

GPO ENABLE

CURRENT DETECT

ROW ENABLE

PORT GPIO

AND

CONSTANT-

CURRENT

LED DRIVE

CURRENT

SOURCE

COLUMN

DRIVES

OPEN­DRAIN

ROW

DRIVES

*GPO

Detailed Description

The MAX7360 is a microprocessor peripheral low-noise
key-switch controller that monitors up to 64 key switches
with optional autorepeat, and key events that are
presented in a 16-byte FIFO. The MAX7360 also features
eight open-drain GPIOs configured for digital I/O or
constant-current output for LED applications up to +14V.

The MAX7360 features an automatic sleep mode and
automatic wakeup that further reduce supply current
consumption. The MAX7360 can be configured to enter
sleep mode after a programmable time following a key
event. The FIFO content is maintained and can be read
in sleep mode. The MAX7360 does not enter autosleep
when a key is held down. The autowake feature takes

To prevent overloading the microprocessor with too
many interrupts, interrupt requests are issued on a
programmable number of FIFO entries, and/or after a
set period of time (Table 10). The key-switch status is
checked 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. INTK functions as an
open-drain general-purpose output (GPO) capable of
driving an LED if key-switch interrupts are not required.

Up to six of the key-switch outputs function as open­drain GPOs capable of driving additional LEDs when
the application requires fewer keys to be scanned. For
each key-switch output used as a GPO, the number of
monitored key switches reduces by eight.

the MAX7360 out of sleep mode following a keypress
event. Enable/disable autosleep and autowake through
the configuration register (Table 8).

8 ______________________________________________________________________________________

On power-up, all control registers are set to power-up
values and the MAX7360 is in sleep mode (Table 1).

Initial Power-Up

I2C-Interfaced Key-Switch Controller and LED

Driver/GPIOs with Integrated ESD Protection

Table 1. Register Address Map and Power-Up Condition

MAX7360

ADDRESS

CODE

(hex)

0x00 Read only 0x3F Keys FIFO Read FIFO key-scan data out

0x01

0x02

0x03

0x04

0x05

0x06

0x40

0x41

0x42

0x43

0x44

0x45

0x46

0x48 Read only 0x00

0x49 Read only 0xFF GPIO input register PORT0–PORT7 input values

0x4A Read only 0x00 Rotary switch count Switch cycles since last read

0x50

0x51

0x52

0x53

0x54

0x55

0x56

0x57

0x58

0x59

0x5A

0x5B

0x5C

0x5D

0x5E

0x5F

READ/
WRITE

R/W

R/W
R/W
R/W
R/W
R/W

R/W

R/W
R/W

R/W

R/W
R/W

R/W

R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W

POWER-UP

VALUE (hex)

0x0A Configuration

0xFF Debounce Key debounce time settling and GPO enable

0x00 Interrupt

0xFE GPO

0x00 Key repeat Delay and frequency for key repeat

0x07 Sleep Idle time to autosleep

0x00

0x00 GPIO control PORT0–PORT7 input/output control

0x00 GPIO debounce PORT0–PORT7 debounce time setting

0xC0

0x00 GPIO output mode PORT0–PORT7 output mode control

0x00 Common PWM Common PWM duty-cycle setting

0x00

0x00 PORT0 PWM PORT0 individual duty-cycle setting

0x00 PORT1 PWM PORT1 individual duty-cycle setting

0x00 PORT2 PWM PORT2 individual duty-cycle setting

0x00 PORT3 PWM PORT3 individual duty-cycle setting

0x00 PORT4 PWM PORT4 individual duty-cycle setting

0x00 PORT5 PWM PORT5 individual duty-cycle setting

0x00 PORT6 PWM PORT6 individual duty-cycle setting

0x00 PORT7 PWM PORT7 individual duty-cycle setting

0x00 PORT0 configuration PORT0 interrupt, PWM mode control and blink period setting

0x00 PORT1 configuration PORT1 interrupt, PWM mode control and blink period setting

0x00 PORT2 configuration PORT2 interrupt, PWM mode control and blink period setting

0x00 PORT3 configuration PORT3 interrupt, PWM mode control and blink period setting

0x00 PORT4 configuration PORT4 interrupt, PWM mode control and blink period setting

0x00 PORT5 configuration PORT5 interrupt, PWM mode control and blink period setting

0x00 PORT6 configuration PORT6 interrupt, PWM mode control and blink period setting

0x00 PORT7 configuration PORT7 interrupt, PWM mode control and blink period setting

REGISTER
FUNCTION

Power-down, key-release enable, autowakeup, and I2C time­out enable

Key-switch interrupt INTK frequency setting
COL2–COL7 and INTK GPO control

GPIO global con-

figuration

GPIO constant-

current setting

Rotary switch con-

figuration

I2C timeout flag I2C timeout since last POR

Rotary switch, GPIO standby, GPIO reset, fade

PORT0–PORT7 constant-current output setting

Rotary switch interrupt frequency and debounce time setting

DESCRIPTION

_______________________________________________________________________________________ 9

I2C-Interfaced Key-Switch Controller and LED
Driver/GPIOs with Integrated ESD Protection

Table 2. Key-Switch Mapping

PIN COL0 COL1 COL2* COL3* COL4* COL5* COL6* COL7*
ROW0
ROW1
ROW2
ROW3
ROW4

MAX7360

ROW5
ROW6
ROW7

*These columns can be configured as GPOs.

KEY 0 KEY 8 KEY 16 KEY 24 KEY 32 KEY 40 KEY 48 KEY 56

KEY 1 KEY 9 KEY 17 KEY 25 KEY 33 KEY 41 KEY 49 KEY 57

KEY 2 KEY 10 KEY 18 KEY 26 KEY 34 KEY 42 KEY 50 KEY 58

KEY 3 KEY 11 KEY 19 KEY 27 KEY 35 KEY 43 KEY 51 KEY 59

KEY 4 KEY 12 KEY 20 KEY 28 KEY 36 KEY 44 KEY 52 KEY 60

KEY 5 KEY 13 KEY 21 KEY 29 KEY 37 KEY 45 KEY 53 KEY 61

KEY 6 KEY 14 KEY 22 KEY 30 KEY 38 KEY 46 KEY 54 KEY 62

KEY 7 KEY 15 KEY 23 KEY 31 KEY 39 KEY 47 KEY 55 KEY 63

Key-Scan Controller

Key inputs are scanned statically, not dynamically,
to ensure low-EMI operation. As inputs only toggle
in response to switch changes, the key matrix can be
routed closer to sensitive circuit nodes.

The key-scan controller debounces and maintains a FIFO
of keypress and release events (including autorepeated
keypresses, if autorepeat is enabled). Table 2 shows the
key-switch order. The user-programmable key-switch
debounce time, and autosleep timer, is derived from the
64kHz clock, which in turn is derived from the 128kHz
oscillator. Time delay for autorepeat and key-switch
interrupt is based on the key-switch debounce time.

Keys FIFO Register (0x00)

The keys FIFO register contains the information pertaining
to the status of the keys FIFO, as well as the key events
that have been debounced (see Table 7 in the Register
Tables section). Bits D0–D5 denote which of the 64 keys
have been debounced and the keys are numbered as in
Table 1.

D7 indicates if there is more data in the FIFO, except
when D5:D0 indicate key 63 or key 62. When D5:D0
indicate key 63 or key 62, the host should read one more
time to determine whether there is more data in the FIFO.
Use key 62 and key 63 for rarely used keys. D6 indicates
if it is a keypress or release event, except when D5:D0
indicate key 63 or key 62.

Reading the key-scan FIFO clears the interrupt INTK
depending on the setting of bit D5 in the configuration
register (0x01).

Configuration Register (0x01)

The configuration register controls the I2C bus timeout
feature, enables key-release detection, enables autowake,

and determines how INTK is deasserted. Write to bit D7
to put the MAX7360 into sleep mode or operating mode.
Autosleep and autowake, when enabled, also change the
status of D7 (see Table 8 in the Register Tables section).

Debounce Register (0x02)

The debounce register sets the time for each debounce
cycle, as well as setting whether the GPO ports are
enabled or disabled. Bits D0–D4 set the debounce time
in increments of 1ms starting at 9ms and ending at 40ms
(see Table 9 in the Register Tables section). Bits D5, D6,
and D7 set which of the GPO ports is enabled. Note the
GPO ports are enabled only in the combinations shown
in Table 9, from all disabled to all enabled.

Key-Switch Interrupt Register (0x03)

The interrupt register contains information related to the
settings of the interrupt request function, as well as the
status of the INTK output, which can also be configured
as a GPO. If bits D0–D7 are set to 0x00, the INTK output
is configured as a GPO that is controlled by bit D1 in the
port register. There are two types of interrupts, the FIFO­based interrupt and time-based interrupt. Set bits D0–D4
to assert interrupts at the end of the selected number of
debounce cycles following a key event (see Table 10 in
the Register Tables section). This number ranges from
1–31 debounce cycles. Setting bits D7, D6, and D5 set
the FIFO-based interrupt when there are 4–16 key events
stored in the FIFO. Both interrupts can be configured
simultaneously and INTK asserts depending on which
condition is met first. INTK deasserts depending on the
status of bit D5 in the configuration register.

Ports Register (0x04)

The ports register sets the values of PORT2–PORT7
and the INTK port, when configured, as open-drain

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