ADP5588-EVALZ Analog Devices Inc, ADP5588-EVALZ Datasheet - Page 24

• Manufacturer Part Number: ADP5588-EVALZ
• Description: Column Keypad Scanner & GPIO Port Expand
• Manufacturer: Analog Devices Inc

Specifications of ADP5588-EVALZ

• Main Purpose: Interface, GPIO Expander
• Embedded: No
• Utilized Ic / Part: ADP5588
• Primary Attributes: 8-Bit 18-Port GPIO Expander
• Secondary Attributes: I²C Interface
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

ADP5588
APPLICATIONS INFORMATION
APPLICATIONS OVERVIEW
The ADP5588 is designed to complement host processors in a
variety of ways. Its versatility makes it the ideal solution for
mobile platforms that require extended keypads and GPIO
expanders. The programmable registers give the designer the
flexibility to configure any or all its GPIOs in a variety of ways.
Figure 17 shows a detailed application diagram.
KEYPAD CURRENT
Keypad current drain varies based on how many keys and how
many rows and columns are pressed during multiple key presses.
Table 52 shows typical current drain for a single press and for
two key presses.
Table 52. Typical Current Drain
Key Presses
1
2
1
T
A
= T
J
= −40°C to +85°C.
PROCESSOR
HOST
Conditions
V
V
CC
CC
V
CC
= 1.8 V to 3.0 V
= 1.8 V to 3.0 V
SCL
SDA
RST
INT
PWM OUTPUT
1
V
CC
V
GPL1
GND
SDA
RST
SCL
V
CC
INT
CC
GPL2
19
21
23
22
20
24
Typical
55
100
A7
B7
C7
D7
E7
F7
G7
H7
J7
I7
1
A6
B6
C6
D6
E6
F6
G6
H6
J6
REGISTERS
I6
2
CONTROL
Figure 17. ADP5588 Detailed Application Block Diagram
A5
B5
C5
D5
G5
H5
E5
F5
J5
I5
3
A4
B4
C4
D4
E4
G4
H4
F4
J4
I4
4
Unit
μA
μA
A3
B3
C3
D3
E3
F3
G3
H3
J3
I3
5
INTERFACE
A2
B2
C2
D2
E2
F2
G2
H2
J2
I2
CONTROL
6
Rev. B | Page 24 of 28
G1
A1
B1
C1
D1
E1
F1
H1
J1
I1
7
G0
A0
B0
C0
D0
E0
F0
H0
J0
I0
8
9
VOLTAGE
VOLTAGE
10
REF
REF
BACKLIGHT CONTROL APPLICATION
Although the ADP5588 is not designed with a backlight driver,
the built-in light sensor comparator inputs, with programmable
registers and trip points, give the backlight designer all the
necessary tools to control the backlight based on lighting con-
ditions or environment. With a few I
can program the device to monitor lighting conditions and
trigger an interrupt based on preset trip points. Once program-
med, the state machine uses these trip points and hysteresis
values to alert the microprocessor of any change in lighting
conditions. In addition to the L2_OUT and L3_OUT bits, four
additional registers (Register 0x3B through Register 0x3E, two
registers per light sensor) provide detailed accounts of the
internal ADC due to light condition changes. The ADC has a
full-scale current of 1000 μA and a dynamic range of 8000,
which translates to 0.125 μA or 0.3125 lux per step. These two
corresponding registers per sensor form a 13-bit register that
can be read to provide detailed translation of the light sensor
input at any instant.
11
12
C9
C8
13
14
ADP5588
15
C9
C8
16
18
17
ENABLE 2 (GPO)
ENABLE (GPO)
C9
C8
BACKLIGHT
0.1µF
0.1µF
2
C commands, the designer
BACKLIGHT
V
DRIVER
CC