MAX6954
4-Wire Interfaced, 2.7V to 5.5V LED Display
Driver with I/O Expander and Key Scan
24 ______________________________________________________________________________________
REGISTER DATA
REGISTER
POWER-UP
CONDITION
ADDRESS
D7 D6 D5 D4 D3 D2 D1 D0
Decode Mode Decode mode enabled 0x01
11111111
Global Intensity 1/16 (min on) 0x02
XXXX0000
Scan Limit Display 8 digits: 0, 1, 2, 3, 4, 5, 6, 7 0x03
XXXXX111
Control Register
Shutdown enabled, blink speed is
slow, blink disabled
0x04
00XX0000
GPIO Data Outputs are low 0x05
XXX00000
Port Configuration
No key scanning, P0 to P4 are all
inputs
0x06
00011111
Display Test Normal operation 0x07
XXXXXXX0
Key_A Mask None of the keys cause interrupt 0x08
00000000
Key_B Mask None of the keys cause interrupt 0x09
00000000
Key_C Mask None of the keys cause interrupt 0x0A
00000000
Key_D Mask None of the keys cause interrupt 0x0B
00000000
Digit Type All are 16 segment or 7 segment 0x0C
00000000
Intensity10 1/16 (min on) 0x10
00000000
Intensity32 1/16 (min on) 0x11
00000000
Intensity54 1/16 (min on) 0x12
00000000
Intensity76 1/16 (min on) 0x13
00000000
Intensity10a 1/16 (min on) 0x14
00000000
Intensity32a 1/16 (min on) 0x15
00000000
Intensity54a 1/16 (min on) 0x16
00000000
Intensity76a 1/16 (min on) 0x17
00000000
Digit 0 Blank digit, both planes 0x60
00100000
Digit 1 Blank digit, both planes 0x61
00100000
Digit 2 Blank digit, both planes 0x62
00100000
Digit 3 Blank digit, both planes 0x63
00100000
Digit 4 Blank digit, both planes 0x64
00100000
Digit 5 Blank digit, both planes 0x65
00100000
Digit 6 Blank digit, both planes 0x66
00100000
Digit 7 Blank digit, both planes 0x67
00100000
Digit 0a Blank digit, both planes 0x68
00000000
Digit 1a Blank digit, both planes 0x69
00000000
Digit 2a Blank digit, both planes 0x6A
00000000
Digit 3a Blank digit, both planes 0x6B
00000000
Digit 4a Blank digit, both planes 0x6C
00000000
Digit 5a Blank digit, both planes 0x6D
00000000
Digit 6a Blank digit, both planes 0x6E
00000000
Digit 7a Blank digit, both planes 0x6F
00000000
Key_A Debounced No key presses have been detected 0x88
00000000
Key_B Debounced No key presses have been detected 0x89
00000000
No key presses have been detected 0x8A
00000000
No key presses have been detected 0x8B
00000000
Key_A Pressed Keys are not pressed 0x8C
00000000
Key_B Pressed Keys are not pressed 0x8D
00000000
Key_C Pressed Keys are not pressed 0x8E
00000000
Key_D Pressed Keys are not pressed 0x8F
00000000
Table 15. Initial Power-Up Register Status