lc75700t Sanyo Semiconductor Corporation, lc75700t Datasheet - Page 15

• Manufacturer Part Number: lc75700t
• Description: Key Scan Ic
• Manufacturer: Sanyo Semiconductor Corporation

2. Interrupt based key data acquisition
(1) Flowchart
(2) Timing chart
Key input
Key scan
CE
DI
DO
NO
Key on
t3
Key data read
Controller
determination
Wait time of
processing
(Key on)
t3: Key scan execution time when the key data agreed for two key scans (615T (s))
t4: Key scan execution time when the key data did not agree for two key scans and
t5: Key address (63H) transfer time
t6: Key data read time
at least t8
DO = "H"
Key OFF
DO = "L"
CE = "L"
CE = "L"
t5
the key scan was executed again. (1230T(s))
Key data read request
Key
address
t6
YES
YES
Key data read
t8
Controller
determination
No
(Key off)
t3
Controller
determination
LC75700T
(Key on)
t5
t6
Key on
t4
t8
Controller
determination
(Key on)
t5
t6
t3
T=
t8
fosc
Controller
determination
1
(Key on)
t5
t6
t8
Controller
determination
(Key off)
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