PT6332 Datasheet, PDF (29/37 Pages) Princeton Technology Corp – VFD Driver/Controller IC

VFD Driver/Controller IC
• Timing Chart
Key Input
Key on
Key on
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PT6332
Key S can
CE
DI
DO
t5
t8
Ke y a ddress
t7
Ke y d ata rea d
t5
t6
t5
t8
t8
t7
t7
t8
t7
Ke y d ata rea d requ est
Co ntro ller
de term inat ion
(key on )
t10
Co ntr o ller
de term inat ion
(key off )
Co ntr o ller
de term inat ion
(key on )
t10
Co ntr o ller
de term inat ion
(key on )
t10
Co ntr o ller
de term inat ion
(key on )
t10
Co ntr o ller
de term inat ion
(key off )
t5 - Key scan execution time (38400T [s]) when the key data for two key scan operations matches.
t6 - Key scan execution time (76800T [s]) when the key data for the first two key scan operations
does not match.
t7 - Key address (8F_H) transfer time
T = ¹ [s]
fosc
t8 - Key data readout time
• Operation
When the controller use interrupt processing for key on/off determination and key data readout, it must
check the state of DO when CE is low, and perform a key data readout if DO is low. The next time the
controller checks the on/off states of the keys, it must make that determination at a time t10 after the
last readout on the state of DO when CE is low, and then read out the key data.
The time t10 must obey the following inequality:
t10 > t6
Note:
1. If the controller reads out key data when DO is high, both the key data (KD1 to KD25) and the sleep
acknowledge data will be invalid data.
PT6332 V1.0
- 29 -
February, 2006