MAX7365 Maxim, MAX7365 Datasheet - Page 7

• Manufacturer Part Number: MAX7365
• Description: The MAX7365 is an I²C-interfaced peripheral that provides microprocessors with management of up to 56 key switches
• Manufacturer: Maxim

The MAX7365 is a microprocessor peripheral low-noise,
key-switch controller that monitors up to 56 key switches
with optional autorepeat. Key events are presented in a
16-byte FIFO. Key-switch functionality can be traded to
provide up to 16 logic inputs. The device features an addi-
tional five GPIOs. Outputs configured as open drain fea-
ture an optional on-chip 100kI pullup/pulldown resistor.
The device features an automatic sleep mode and auto-
matic wakeup that further reduce supply current con-
sumption. The device 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. When a key is held down,
Table 1. Register Address Map and Power-Up Condition
CODE (hex)
ADDRESS
0x3A
0x3B
0x3C
0x00
0x01
0x02
0x03
0x05
0x06
0x30
0x31
0x32
0x33
0x34
0x35
0x36
0x37
0x38
0x39
Read only
Read only
Read only
WRITE
READ/
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
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Detailed Description
VALUE (hex)
POWER-UP
Key-Switch Controller with GPIO Ports
0x3F
0x0B
0xFF
0x00
0x00
0x07
0xF7
0x00
0x00
0xFF
0x7F
0x1F
0x1F
0xFF
0x7F
0x00
0x00
0x00
0x00
GPIs MSB Interrupt Mask GPI[14:8] (ROW[7:1]) port interrupt mask for inputs
GPIs LSB Interrupt Mask GPI[7:0] (ROW0, COL[6:0]) port interrupt mask for inputs
Key-Switch Autorepeat Delay and frequency for key repeat
Key-Switch Debounce Key debounce time setting
Key-Switch Array Size Keyscan switch array size
GPIs Interrupt Trigger GPIO edge-triggered interrupt setting
Key-Switch Interrupt
GPIs Interrupt Mask
GPIs MSB Interrupt
Open-Drain Enable
GPO Output Mode
GPIs LSB Interrupt
GPIs MSB Value
GPIs LSB Value
GPO High-Side
GPIO Direction
Configuration
Trigger Mode
Trigger Mode
GPIO Value
REGISTER
FUNCTION
Keys FIFO
Autosleep
1MHz I
Read FIFO keyscan data out
Power-down, interrupt clearing mode, key-release enable,
autowake, and I
Key-switch interrupt and INT frequency setting
Idle time to autosleep
Select GPIO port as input mode or output mode
GPO open-drain/push-pull output setting for GPIO port
GPI[7:0] (ROW0, COL[6:0]) port input values
GPI[14:8] (ROW[7:1]) port input values
Debounced input or output values for GPIO port
GPIO port interrupt mask for inputs
GPI[7:0] (ROW0, COL[6:0]) edge-triggered interrupt setting
GPI[14:8] (ROW[7:1]) edge-triggered interrupt setting
GPIO port output mode high-side open-drain setting
the device cannot enter autosleep. The autowake feature
takes the device out of sleep mode following a keypress
event. Autosleep and autowake can be disabled.
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 microproces-
sor with too many interrupts. The key-switch status 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. Interrupts
are configurable per each input port with edge detection.
On power-up, all control registers are set to power-up
values
(Table
2
2
C timeout enable
1), and the device is in sleep mode.
C-Interfaced 8 x 7
DESCRIPTION
Register Description
MAX7365