PT6552 查看數據表（PDF） - Princeton Technology

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PT6552

1/2 Duty LCD Driver with On-Chip Key Input Function

Princeton Technology 

PT6552

2. CONTROLLER KEY DATA READING UNDER INTERRUPT CONTROL

When determining key on/of and reading key data, the controller must confirm the state of DO output when CE is low.

When DO is low, the controller recognizes that a key has been pressed and reads the key data. After the time t8, the next

key on/off determination and reading key data must be confirmed by the state of DO output when CE is low. During this

operation t8 must obey the following condition:

t8 > t4.

If key data is read when DO is high, the key data (KD1 to KD30) and the sleep acknowledge data (SA) be invalid.

FLOWCHART

TIMING CHART

T=1/fosc

t3: Key scan execution time (800T [s]) when the key scan data for two key scans agrees.

t4: Key scan execution time (1600T [s]) when the key scan data for two key scans does not agree and a key scan is

executed again.

t5: Key address (43H) transfer time.

t6: Key data read time.

V1.3

15

July 2010

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