lc75857e Sanyo Semiconductor Corporation, lc75857e Datasheet - Page 38

• Manufacturer Part Number: lc75857e
• Description: 1/3, 1/4 Duty Lcd Display Drivers With Key Input Function
• Manufacturer: Sanyo Semiconductor Corporation

2. Interrupt based key data acquisition
(1) Flowchart
(2) Timing chart
Key input
Key scan
CE
DI
DO
t5: Key scan execution time when the key data agreed for two key scans. (615T(s))
t6: Key scan execution time when the key data did not agree for two key scans and the key scan was executed again. (1230T(s))
t7: Key address (43H) transfer time
t8: Key data read time
NO
Key on
Key data read
t5
determination
processing
Wait for at
DO = [H]
DO = [L]
CE = [L]
Controller
CE = [L]
least t10
Key OFF
(Key on)
t7
Key data read request
YES
YES
Key address
t8
Key data read
t10
NO
determination
Controller
(Key off)
T =——— = ——
LC75857E, LC75857W
fosc
1
t5
determination
Controller
(Key on)
f
CK
1
t7
t8
Key on
t6
t10
determination
Controller
(Key on)
t7
t8
t5
t10
determination
Controller
(Key on)
t7
t8
t10
determination
No. 7980-38/39
Controller
(Key off)