Datasheet

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