|Beschreibung||1/4 Duty LCD Display Drivers with Key Input Function|
|Hersteller||Sanyo Semicon Device|
Gesamt 25 Seiten
Ordering number : ENN5066B
1/4 Duty LCD Display Drivers
with Key Input Function
The LC75854E and LC75854W are 1/4 duty LCD display
drivers that can directly drive up to 164 segments and can
control up to four general-purpose output ports. These
products also incorporate a key scan circuit that accepts
input from up to 30 keys to reduce printed circuit board
• Key input function for up to 30 keys (A key scan is
performed only when a key is pressed.)
• 1/4 duty - 1/2 bias and 1/4 duty - 1/3 bias drive schemes
can be controlled from serial data (up to 164 segments).
• Sleep mode and all segments off functions that are
controlled from serial data
• Segment output port/general-purpose output port
function switching that is controlled from serial data
• Serial data I/O supports CCB format communication
with the system controller.
• Direct display of display data without the use of a
decoder provides high generality.
• Provision of an on-chip voltage-detection type reset
circuit prevents incorrect displays.
• RC oscillator circuit
• CCB is a trademark of SANYO ELECTRIC CO., LTD.
• CCB is SANYO’s original bus format and all the bus
addresses are controlled by SANYO.
Any and all SANYO products described or contained herein do not have specifications that can handle
applications that require extremely high levels of reliability, such as life-support systems, aircraft’s
control systems, or other applications whose failure can be reasonably expected to result in serious
physical and/or material damage. Consult with your SANYO representative nearest you before using
any SANYO products described or contained herein in such applications.
SANYO assumes no responsibility for equipment failures that result from using products at values that
exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other
parameters) listed in products specifications of any and all SANYO products described or contained
SANYO Electric Co.,Ltd. Semiconductor Company
TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110-8534 JAPAN
O3099TH (OT)/N3095HA (OT)/52295TH (OT) No. 5066-1/25
Pin Pin No.
S1/P1 to S4/P4
S5 to S39
1 to 4
5 to 39
Segment outputs for displaying the display data transferred by serial data
The S1/P1 to S4/P4 pins can be used as general-purpose output ports
under serial data control.
Common driver outputs
The frame frequency fO is given by: fO = (fOSC/512) Hz.
I/O when unused
— O Open
— O Open
KS3 to KS6
46 to 49
Key scan outputs
Although normal key scan timing lines require diodes to be inserted in the
timing lines to prevent shorts, since these outputs are unbalanced CMOS
transistor outputs, these outputs will not be damaged by shorting when
these outputs are used to form a key matrix. The KS1/S40 and KS2/S41
pins can be used as segment outputs when so specified by the control data.
KI1 to KI5
50 to 54
Key scan inputs
These pins have built-in pull-down resistors.
An oscillator circuit is formed by connecting an external resistor and
capacitor at this pin.
Serial data interface connections to the controller. Note that DO, being an
open-drain output, requires a pull-up resistor.
CE: Chip enable
CL: Synchronization clock
DI: Transfer data
DO: Output data
This pin must be connected to ground.
Used for applying the LCD drive 2/3 bias voltage externally. Must be
connected to VDD2 when a 1/2 bias drive scheme is used.
Used for applying the LCD drive 1/3 bias voltage externally. Must be
connected to VDD1 when a 1/2 bias drive scheme is used.
Power supply connection. Provide a voltage of between 4.5 and 6.0 V.
Power supply connection. Connect to ground.
H I GND
— I/O VDD
— O Open
— I Open
— I Open
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 384 T (s). To reliably determine the on/off state of the keys, the LC75854E/W 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) 800 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 LC75854E/W cannot detect a key press shorter than 800 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 800 T (s) (where T = 1 ) the LC75854E/W outputs a key data read 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 LC75854E/W
performs another key scan. Also note that DO, being an open-drain output, requires a pull-up resistor (between 1
and 10 kΩ).
|Seiten||Gesamt 25 Seiten|
|PDF Download||[ LC75854W Schematic.PDF ]|
|LC75854E||1/4 Duty LCD Display Drivers with Key Input Function|
Sanyo Semicon Device
|LC75854W||1/4 Duty LCD Display Drivers with Key Input Function|
Sanyo Semicon Device
Hex D-Type Flip-Flop / Quad D-Type Flip-Flop.
EPITAXIAL PLANAR NPN TRANSISTOR.
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