ADP5589 Analog Devices, ADP5589 Datasheet - Page 11

• Manufacturer Part Number: ADP5589
• Description: Keypad Decoder and I/O Expansion
• Manufacturer: Analog Devices

Specifications of ADP5589

• Vin Range: 1.8 to 3.0V
• Number Of I/os: 19
• Application: Mobil I-0 Exp-Keybd Cont,Mobil I-O Expander
• Qwerty Keypad: Yes
• Other Functions: I2C I/O & register
• Function Flag: Mobil I-O
• Package: 24-Lead LFCSP,25-Ball WLCSP

Use Registers PIN_CONFIG_A[7:0] (0x49),
PIN_CONFIG_B[7:0] (0x4A), and PIN_CONFIG_C[2:0]
(0x4B) to configure I/Os for keypad decoding. The number
label on each key switch represents the event identifier that
is recorded if that switch is pressed. If all row/column pins
are configured, it is possible to observe all 88 key identifiers on
the FIFO.
If a smaller 3 × 3 matrix is configured, for example, using the
C5, C6, and C7 column pins and the R1, R2, and R3 row pins,
only the nine event identifiers (17, 18, 19, 28, 29, 30, 39, 40,
and 41) can possibly be observed on the FIFO, as shown in
Figure 11.
By default, the
FIFO. Figure 12 illustrates what happens when a single key is
pressed and released. Initially, the key scanner is idle. When
Key 32 is pressed, the scanner begins scanning through all
configured row/column pairs. After the scan wait time, the
scanner again scans through all configured row/column pairs
and detects that Key 32 has remained pressed, which sets the
EVENT_INT interrupt. The event counter, EC[4:0], is incre-
mented to 1, EVENT1[7:0] of the FIFO is updated with its event
identifier set to 32, and its Event1_State bit is set to 1, indicating
a press.
ADP5589
records key presses and releases on the
RESET_TRIGGER_TIME[2:0]
89
90
91
92
93
94
95
96
EXT_LOCK_EVENT[7:0]
RESET1_EVENT_A[7:0]
RESET1_EVENT_B[7:0]
RESET1_EVENT_C[7:0]
RESET2_EVENT_A[7:0]
RESET2_EVENT_B[7:0]
INT_MASK_TIMER[4:0]
12
23
34
45
56
67
78
C0 C1 C2 C3 C4 C5 C6 C7 C8 C9 C10
1
UNLOCK_TIMER[2:0]
PIN_CONFIG_A[7:0]
PIN_CONFIG_B[7:0]
PIN_CONFIG_C[2:0]
13
24
35
46
57
68
79
2
UNLOCK1[7:0]
UNLOCK2[7:0]
14
25
36
47
58
69
80
3
LOCK_EN
15
26
37
48
59
70
81
4
16
27
38
49
60
71
82
SINK ON/OFF
5
COLUMN
Figure 11. Detailed Key Scan Block
17
28
39
50
61
72
83
6
I/O CONFIGURATION
18
29
40
51
62
73
84
7
KEY SCAN
CONTROL
Rev. A | Page 11 of 48
19
30
41
52
63
74
85
8
20
31
42
53
64
75
86
9
SENSE
ROW
10
21
32
43
54
65
76
87
LOGIC EVENT
KEY EVENT
11
22
33
44
55
66
77
88
GPI EVENT
I
2
RESET 1_INITIATE
RESET 2_INITIATE
LOCK_STAT
LOCK_INT
EVENT_INT
C BUSY?
The key scanner continues the scan/wait cycles while the key
remains pressed. If the scanner detects that the key has been
released for two consecutive scan cycles, the event counter
EC[4:0] is incremented to 2, and EVENT2[7:0] of the FIFO is
updated with its event identifier set to 32. Its Event2_State bit is
set to 0, indicating a release. The key scanner goes back to idle
mode because no other keys are pressed.
The EVENT_INT interrupt can be triggered by both press and
release key events. As shown in Figure 13, if Key 32 is pressed,
EVENT_INT is asserted, EC[4:0] is updated, and the FIFO is
updated. During the time that the key is still pressed, it is
possible for the FIFO to be read, the event counter decremented
to 0, and EVENT_INT cleared. When the key is finally released,
EVENT_INT is asserted, the event counter incremented, and
the FIFO updated with the release event information.
EVENT_INT
R0
KEY SCAN
R1 R2
EC[4:0]
KEY 32
UPDATE
R3
FIFO
R4
KEY 32 RELEASE
R5 R6
KEY 32 PRESS
Figure 12. Press and Release Event
OVRFLOW_INT
R7
EC[4:0]
FIFO
1
0
0
0
FIFO
32
32
0
0
1
ADP5589
2