MAX6954 Maxim, MAX6954 Datasheet - Page 29

• Manufacturer Part Number: MAX6954
• Description: 4-Wire Interfaced / 2.7V to 5.5V LED Display Driver with I/O Expander and Key Scan
• Manufacturer: Maxim

Table 32. Port Configuration Register Format
Table 33. Key Mask Register Format
GPIO
Configuration
Register
PORT ALLOCATION OPTIONS
0 Keys Scanned
8 Keys Scanned
16 Keys Scanned
24 Keys Scanned
32 Keys Scanned
EXAMPLE PORT CONFIGURATION SETTINGS
No Keys
Scanned, P4 and
P2 Are Outputs,
Others Are Inputs
8 Keys Scanned,
P3 and P1 Are
Outputs, P2 Is an
Input
32 Keys
Scanned, No
GPIO Ports
Key_C Mask
Key_D Mask
Key_A Mask
Key_B Mask
REGISTER
Register
Register
Register
Register
MASK
KEY
MODE
4-Wire Interfaced, 2.7V to 5.5V LED Display
ADDRESS
______________________________________________________________________________________
CODE
(HEX
0x08
0x09
0x0A
0x0B
CODE (HEX)
Driver with I/O Expander and Key Scan
ADDRESS
0x06
0x06
0x06
0x06
0x06
0x06
0x06
0x06
0x06
SW_ D7
SW_A7
SW_B7
SW_C7
D7
Set number of keys scanned
D7
0
0
0
0
1
0
0
1
SW_C6
SW_D6
SW_A6
SW_B6
D6
D6
0
0
1
1
X
0
0
X
WITH APPROPRIATE SWITCH NAMED BELOW
SW_A5
SW_B5
SW_C5
SW_D5
D5
D5
X
X
0
1
0
1
0
1
SW_A4
SW_B4
SW_C4
SW_D4
REGISTER DATA
D4
Set port direction for ports P0 to P4:
0 = output, 1 = input
REGISTER DATA
IRQ
IRQ
IRQ
IRQ
D4
P4
0
X
X
SW_C3
SW_D3
SW_A3
SW_B3
D3
Key_D
D3
P3
P3
P3
P3
X
1
0
SW_A2
SW_B2
SW_C2
SW_D2
D2
Key_C
Key_C
D2
P2
P2
P2
X
0
1
SW_A1
SW_B1
SW_C1
SW_D1
Key_B
Key_B
Key_B
D1
D1
P1
P1
1
0
X
SW_C0
SW_D0
SW_A0
SW_B0
Key_A
Key_A
Key_A
Key_A
D0
D0
P0
X
X
1
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