LC75817E Datasheet, PDF (40/43 Pages) Sanyo Semicon Device – 1/8 to 1/10 Duty Dot Matrix LCD Display Controller/Driver with Key Input Function

2. Interrupt based key data acquisition
• Flowchart
LC75817E, 75817W
CE = L
NO
DO = L
YES
Key data read
processing
Wait for at least t10
CE = L
NO
DO = H
YES
Key off
• Timing chart
Key input
Key on
Key on
Key scan
CE
DI
DO
t5
t5
t6
t5
t8
Key address
t7
Key data read
t8
t7
Key data read request
t10
Controller
determination
(Key on)
Controller
determination
(Key off)
Controller
determination
(Key on)
t8
t7
t10
Controller
determination
(Key on)
t8
t7
t10
Controller
determination
(Key on)
t10
Controller
determination
(Key off)
t5: Key scan execution time when the key data agreed for two key scans. (4800T(s))
t6: Key scan execution time when the key data did not agree for two key scans and the key scan was executed again. (9600T(s))
t7: Key address (43H) transfer time
t8: Key data read time
1
T = ———
fosc
No. 6144-40/43