AK4184 Datasheet, PDF (32/36 Pages) Asahi Kasei Microsystems – TSC with Keypad Scanner and GPIO Expander

■ Keypad Scanner Flowchart
1. Host Scan
Keypad
Touch
No
Read
KPDATA1,2
Register?
Yes
KEYIRQN pin
Low
Write
KPScanInitiate
Register
Start Clock
BUSY pin
High
Start
Scanning &
Debouncing keys
Store scan results
in KPDATA1, 2
Register
BUSY pin
Low
Stop Clock
KEYIRQN pin
High
Done
Figure 19. Keypad scanner sequence initiated by Host command
[AK4184]
MS0603-E-00
32
2007/04