MAX6954
4-Wire Interfaced, 2.7V to 5.5V LED Display
Driver with I/O Expander and Key Scan
28 ______________________________________________________________________________________
REGISTER DATA
DUTY
CYCLE
TYPICAL
SEGMENT
CURRENT (mA)
D7 D6 D5 D4 D3 D2 D1 D0
CODE
1/16 (min on) 2.5 0x10 to 0x17 0 0 0 0
0x0X
2/16 5 0x10 to 0x17 0 0 0 1
0x1X
3/16 7.5 0x10 to 0x17 0 0 1 0
0x2X
4/16 10 0x10 to 0x17 0 0 1 1
0x3X
5/16 12.5 0x10 to 0x17 0 1 0 0
0x4X
6/16 15 0x10 to 0x17 0 1 0 1
0x5X
7/16 17.5 0x10 to 0x17 0 1 1 0
0x6X
8/16 20 0x10 to 0x17 0 1 1 1
0x7X
9/16 22.5 0x10 to 0x17 1 0 0 0
0x8X
10/16 25 0x10 to 0x17 1 0 0 1
0x9X
11/16 27.5 0x10 to 0x17 1 0 1 0
0xAX
12/16 30 0x10 to 0x17 1 0 1 1
0xBX
13/16 32.5 0x10 to 0x17 1 1 0 0
0xCX
14/16 35 0x10 to 0x17 1 1 0 1
0xDX
15/16 37.5 0x10 to 0x17 1 1 1 0
0xEX
15/16 (max on) 37.5 0x10 to 0x17 1 1 1 1
See Table 28.
0xFX
Table 29. Odd Individual Segment Intensity Format
REGISTER DATA
MODE
ADDRESS
CODE (HEX)
D7 D6 D5 D4 D3 D2 D1 D0
Write GPIO Data 0x05 X X X P4 P3 P2 P1 P0
Read GPIO Data
P4 or IRQ status
Table 30. GPIO Data Register
KEYS
SCANNED
PORTS
AVAILABLE
P0 P1 P2 P3 P4
None 5 pins GPIO GPIO GPIO GPIO GPIO
1 to 8 3 pins Key_A GPIO GPIO GPIO IRQ
9 to 16 2 pins Key_A Key_B GPIO GPIO IRQ
17 to 24 1 pin Key_A Key_B Key_C GPIO IRQ
25 to 36 None Key_A Key_B Key_C Key_D IRQ
Table 31. Port Scanning Function Allocation