msm9223 Oki Semiconductor, msm9223 Datasheet - Page 21

• Manufacturer Part Number: msm9223
• Description: 27-bit Duplex/triplex Vfd Controller/driver With Digital Dimming, Adc And Keyscan
• Manufacturer: Oki Semiconductor

¡ Semiconductor
Keyscan
Keyscanning is started only when depression or release of any key is detected in order to
minimize noise caused by scanning signal. Then, keyscanning is continued until the keyscan
stop mode is sent from a microcomputer. The INT pin goes to the high level at the completion
of 1-cycle scanning after the keyscan start, so the (high level) signal sent from the INT pin can be
used as an interrupt signal.
[Keyscan Timing]
Note: Keyscanning cannot be stopped by selecting the keyscan stop mode only once if:
INT
CS
Depress
- keyscanning is started after depression or release of any key is detected, and then
- a key is depressed or released again before the keyscan stop mode is selected.
To stop keyscanning, it is required to select the keyscan stop mode once again.
ROW 0
ROW 1
ROW 2
ROW 3
ROW 4
INT
MODE5 : Keyscan stop
Keyscan
MODE5
Depress/Release
1 Cycle
Depress
Release
Keyscan
MODE5
Keyscan stop mode
is selected.
MODE5
MSM9223
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