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Pin Descriptions
Pin Name
V
DD
V
SS
V
EE
Y1 to Y20
Y21 to Y40
V1, V2
V3, V4
V5, V6
L/R1
Function
Logic circuitry power supply (+5 V
±
10%)
0 V
LCD driver power supply (–4 to –6 V)
Channel 1 LCD driver output pins
Channel 2 LCD driver output pins
Reference voltage for selected driver outputs
Reference voltage for non-selected driver outputs (channel 1)
Reference voltage for non-selected driver outputs (channel 2)
Shift direction for channel 1 shift register
L/R2
Shift direction for channel 2 shift register
LDATA1
RDATA1
LDATA2
RDATA2
M
CLK
LA
Serial data input/output pins for channel 1 shift register
Serial data input/output pins for channel 2 shift register
Switching clock signal for LCD driver.
Latches channael 1 data on the falling edge.
This also will latch channel 2 data on the falling edge if CH2-BP is low.
Shift channel 1 data on the falling edge.
This also will shift channel 2 data on the falling edge if CH2-BP is low.
Switches the mode of channel 2.
Exchanges the latch signal for the shift signal of channel 2 and invert the M signal.
Channel 2, then, can be used as a scan-line driver.
CLK
SR
CH2-BP
L/R1
LDATA1
Output
Input
RDATA1
Input
Output
High-level
Low-level
L/R2
LDATA2
Output
Input
RDATA2
Input
Output
High-level
Low-level
CH2-BP
Channel 2
M
Latch
Shift
High
CLK
SR
CLK
LA
M
For scan-line driver
Low
CLK
LA
CLK
SR
M
For signal line driver
Functional Description
LC7930N, LC7930NW are serial data transfer type LCD drivers.
Data inputted serially from the data pin is shifted successively by the synchronizing clock (CLK
SR
) and latched by the latch clock
(CLK
LA
) when the all data are shifted.
.
Segment terminal
When CH2-BP goes to low, the data of channel 1 and channel 2 are shifted at the falling edge of CLK
SR
, and then latched at
the falling edge of the CLK
LA
. The reference pulse will be switched to selected or unselected due to the latched data.
.
Scan terminal
When CH2-BP goes to high, the data of channel 2 is shifted at the rising edge of CLK
LA
, and then latched at the rising edge of
the CLK
SR
. When FLM signal, as a data, is inputted, the output will be scan terminal drive mode.
Continued on next page.
LC7930N, 7930NW
No.2778-5/7