LC75853NW View Datasheet(PDF) - SANYO -> Panasonic
Part Name
Description
Manufacturer
LC75853NW Datasheet PDF : 24 Pages
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LC75853NE, 75853NW
Sleep Mode Functions
Sleep mode is set up by setting S0 or S1 in the control data to 1. The segment outputs will all go low and the common
outputs will also go low, and the oscillator on the OSC pin will stop (it will be started by a key press). This reduces
power dissipation. This mode is cleared by sending control data with both S0 and S1 set to 0. However, note that the
S1/P1 to S4/P4 outputs can be used as general-purpose output ports according to the state of the P0 and P1 control data
bits, even in sleep mode. (See the control data description for details.)
Key Scan Operation Functions
1. Key scan timing
The key scan period is 288 T (s). To reliably determine the on/off state of the keys, the LC75853NE/NW scans the
keys twice and determines that a key has been pressed when the key data agrees. It outputs a key data read request (a
low level on DO) 615 T (s) after starting a key scan. If the key data does not agree and a key was pressed at that
point, it scans the keys again. Thus the LC75853NE/NW cannot detect a key press shorter than 615 T (s).
Note: *3. In sleep mode the high/low state of these pins is determined by the S0 and S1 bits in the control data. Key scan output signals are not output
from pins that are set low.
2. In normal mode
• The pins KS1 to KS6 are set high
• When a key is pressed a key scan is started and the keys are scanned until all keys are released. Multiple key
presses are recognized by determining whether multiple key data bits are set.
• If a key is pressed for longer than 615 T (s) (where T = 1 ) the LC75853NE/NW outputs a key data read
fOSC
request (a low level on DO) to the controller. The controller acknowledges this request and reads the key data.
However, if CE is high during a serial data transfer, DO will be set high.
• After the controller reads the key data, the key data read request is cleared (DO is set high) and the
LC75853NE/NW performs another key scan. Also note that DO, being an open-drain output, requires a pull-up
resistor (between 1 and 10 kΩ).
No. 4967-11/24
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