lc75864w Sanyo Semiconductor Corporation, lc75864w Datasheet - Page 13

• Manufacturer Part Number: lc75864w
• Description: 1/4 Duty Lcd Display Drivers With Key Input Function
• Manufacturer: Sanyo Semiconductor Corporation

3. In sleep mode
Key input 1
Key input 2
Key scan
• The pins KS1 to KS6 are set to high or low by the S0 and S1 bits in the control data. (See the control data
• If a key on one of the lines corresponding to a KS1 to KS6 pin which is set high is pressed, the oscillator on the
• If a key is pressed for longer than 800 T (s) (where T =
• After the controller reads the key data, the key data read request is cleared (DO is set high) and the LC75864E/W
• Sleep mode key scan example
description for details.)
OSC pin is started and a key scan is performed. Keys are scanned until all keys are released. Multiple key presses
are recognized by determining whether multiple key data bits are set.
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.
performs another key scan. However, this does not clear sleep mode. Also note that DO, being an open-drain
output, requires a pull-up resistor (between 1 and 10 k ).
Example: S0 = 0, S1 = 1 (sleep with only KS6 high)
Note *4. These diodes are required to reliable recognize multiple key presses on the KS6 line when sleep mode state with only KS6 high, as in the
CE
DI
DO
Serial data transfer
above example. That is, these diodes prevent incorrect operations due to sneak currents in the KS6 key scan output signal when keys on
the KS1 to KS5 lines are pressed at the same time.
800T(s)
Key data read request
Serial data transfer
Key address (43H)
Key data read
LC75864E, 75864W
Serial data transfer
800T(s)
f
OSC
1
Key data read request
When any one of these keys is pressed, the
oscillator on the OSC pin is started and the keys
are scanned.
) the LC75864E/W outputs a key data read request (a
Key address
Key data read
800T(s)
Key data read request
Key address
Key data read
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T=
fosc
1