Datasheet

Figure 8. Key-Scan Timing Diagram
Figure 7. Key-Scanning Configuration
LED OUTPUT O0
LED OUTPUT O1
LED OUTPUT O2
LED OUTPUT O3
LED OUTPUT O4
LED OUTPUT O5
LED OUTPUT O6
LED OUTPUT O7
12.5µs TO 187.5µs DIGIT PERIOD
1.6ms MULTIPLEX CYCLE 1 1.6ms MULTIPLEX CYCLE 2 1.6ms MULTIPLEX CYCLE 8
THE FIRST HALF OF A 25.6ms KEY-SCAN CYCLE
1.6ms MULTIPLEX CYCLE 8
THE SECOND HALF OF A 25.6ms KEY-SCAN CYCLE
1.6ms MULTIPLEX CYCLE 1
START OF NEXT KEY-SCAN CYCLE
FIRST TEST OF KEY SWITCHES SECOND TEST OF KEY SWITCHES
INTERRUPT ASSERTED IF REQUIRED
DEBOUNCE REGISTER UPDATED
C
A
A
B
D E
SW A0
SW A1
SW A2
SW A3
SW A4
SW A5
SW A6
SW A7
P0
V
CC
LED OUTPUT O0
LED OUTPUT O1
LED OUTPUT O2
LED OUTPUT O3
LED OUTPUT O4
LED OUTPUT O5
LED OUTPUT O6
LED OUTPUT O7
P1
P2
P3
P4
MICROCONTROLLER INTERRUPT
SW B0
SW B1
SW B2
SW B3
SW B4
SW B5
SW B6
SW B7
SW C0
SW C1
SW C2
SW C3
SW C4
SW C5
SW C6
SW C7
SW D0
SW D1
SW D2
SW D3
SW D4
SW D5
SW D6
SW D7
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Maxim Integrated │ 17
MAX6954 4-Wire Interfaced, 2.7V to 5.5V LED Display
Driver with I/O Expander and Key Scan