PT6552 Datasheet, PDF (9/22 Pages) Princeton Technology Corp – ½ Duty LCD Driver with On-Chip Key Input Function

PT6552
OUTPUT DATA
KD1 TO KD30: KEY DATA
When a key matrix with up to 30 keys is formed using the KS1 to KS6 output pins and the KI1 to KI5 input pins, the key
data corresponding to given key will be 1 if that key is pressed. The table below lists that correspondence.
Item
KS1/SG44
KS2/SG45
KS3
KS4
KS5
KS6
KI1
KD1
KD6
KD11
KD16
KD21
KD26
KI2
KD2
KD7
KD12
KD17
KD22
KD27
KI3
KD3
KD8
KD13
KD18
KD23
KD26
KI4
KD4
KD9
KD14
KD19
KD24
KD29
KI5
KD5
KD10
KD15
KD20
KD25
KD30
When the output pins KS1/SG44 and KS2/SG45 are selected for segment output by the control data K0 and K1, the key
data items KD1 to KD10 will be 0.
SA: SLEEP ACKNOWLEDGE DATA
This output data is set according to the state when the key was pressed. If the LSI was in sleep mode, SA will be 1, and
if the LSI was in normal mode, SA will be 0.
SLEEP MODE
When S0 or S1 in the control data is set to 1, the oscillator at the OSC pin will stop (it will restart if a key is pressed) and
the segment and common outputs will all go to the low level. This reduces the LSI power dissipation. However, the
SG1/P1 to SG4/P4 output pins can be used as general-purpose output ports even in sleep mode if selected for such use
by the P0 and P1 control data bits
KEY SCAN OPERATING
KEY SCAN TIMING
The key scan period is 375T[s]. The key scan is performed twice to reliably determine the key on/off states, and the LSI
detects key data agreement. When the key data agrees, the LSI determines that a key has been pressed, and outputs a
key read request (by setting DO low) 800T[s] after the key scan started. If a key is pressed again without the key data
agreeing, a key scan is performed 1=once more. Thus key on/off operations shorter than 800T[s] cannot be detected.
Note:
*1: The high or low states of these signals in sleep mode are determined by the S0 and S1 control data bits.
V1.3
9
July 2010