Datasheet

Data Sheet ADP5588
Rev. C | Page 11 of 28
START
MASK TIMER = 0
KEY PRESS
DETECTED
NO
NO
YES
NO
NO
NO
YES
YES
YES
NO
YES
YES
YES
NO
YES
YES
NO
NO
YES
YES
NO
GENERATE
KE INTERRUPT
START MASK TIMER
MASK TIMER
EXPIRES
MASK TIMER
EXPIRES
GENERATE
KEYLOCK INTERRUPT
FIRST UNLOCK
KEY DETECTED
SECOND UNLOCK
KEY DETECTED
START UNLOCK1 TO UNLOCK2
UNLOCK1 TO
UNLOCK2
TIMER EXPIRES
KEY PRESS
DETECTED
START UNLOCK1 TO UNLOCK2
FIRST UNLOCK
KEY DETECTED
GENERATE
KEYLOCK INTERRUPT
SECOND UNLOCK
KEY DETECTED
UNLOCK1 TO
UNLOCK2
TIMER EXPIRES
NO
07673-015
Figure 10. Keypad Lock Interrupt Mask Timer Flowchart
Debouncing
The ADP5588 has a 50 μs debounce time for GPIOs configured
as GPIs and rows in keypad scanning mode. The reset line
always has a 50 μs debounce time.
General Purpose Outputs (GPOs)
The ADP5588 allows the user to configure all or some of its
GPIOs as GPOs. These GPOs can be used as extra enables for
the host processor or simply as trigger outputs. When configured
as an output (GPO), a digital buffer drives the pin to 0 V for a 0
and to V
CC
for a 1. To s et any GPIO as a GPO, make sure that
the corresponding bits in Register 0x1D through Register 0x1F are
set for GPIO mode; then use Register 0x23 through Register 0x25
to set the corresponding bits for GPO mode.
Power-On Reset
For built-in power-up initialization for applications lacking a
power-on reset signal, a reset pin,
RST
, allows the user to reset
the registers to default values in the event of a brownout or
other reset conditions.
Ambient Light Sensing
The ADP5588 has built in light sensor comparator inputs to
detect ambient light conditions. An ADC samples the output of
external photosensors connected to the comparator inputs, and
the result is fed into programmable trip comparators. The ADC
has an input range of 0 μA to 1000 μA (typical). The device can
handle up to two photosensors (use Register 0x30 through
Register 0x3A to configure the photosensor inputs).