PT6553_10 Datasheet, PDF (15/41 Pages) Princeton Technology Corp – LCD Driver IC with Key Input Function

LCD Driver IC with Key Input Function
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URL: http://www.princeton.com.tw
PT6553
SLEEP MODE FUNCTION
The Sleep Mode is activated by setting S0 or S1 to "1". Both the segment and common outputs will be
"LOW" and oscillation operation will stop reducing the power dissipation. However, oscillation
operation will be activated again when a key is pressed. The Sleep Mode is deactivated when both S0
and S1 bits are set to "0". It should be noted that even in the Sleep Mode, the SG1/P1 to SG4/P4 pins
can also be used as General Purpose Output Ports depending on the states of the P0 and P1 control
data bits. Please refer to the control data section for details.
KEY SCAN OPERATION
KEY SCAN TIMING
The key scan period is 288T (s). The key is scanned twice and when the key data is in agreement with
the key that has been pressed, then the key operation is valid. The key data read request (DO is set to
"LOW") is outputted after starting a key scan operation. If the key data is not in agreement with the key
that has been pressed, the PT6553 scans the key again. PT6553 can only detect a key press longer
than or equal to 615T (s). Please refer to the diagram below.
KO1
KO2
KO3
KO4
KO5
*1
*
2
*
3
*
4
*
5
1
*
2
*
3
*
4
*
5
*
KO6
6
6
576T (s)
KEY ON
Note:
* = During the Sleep Mode Condition, the States ("HIGH" or "LOW") of these pins are determined by
the control data bits -- S0 and S1 bits. When these pins are set to "LOW" State the key scan output
signals are not outputted.
PT6553 V1.7
- 15 -
November, 2007