Specifications

5–24 EPSON
SED1225 Series
LED RAM (Register)
The SED1225 has the LED drive functions to drive the
LCD by controlling the XLE1 and XLE2 pins.
The following provides the relationship between the
RAM address and write data by LED register setup.
The following defines the XLE1 and XLE2 pin state
depending on the TIM1, TIM2, LED1 and LED2 set
values.
Electronic Control RAM (Register)
The SED1225 has the electronic control functions to
control LCD drive voltages and to adjust the LCD
display density. One of 32-state LCD voltages can be
selected when the 5-bit data is written in the Electronic
Control RAM.
The following provides the relationship between the
RAM address and write data by electronic control setup.
000
28H
29H
Electronic
Control
00 0 V
REG-0
V
REG-α
V
REG-2α
V
REG-29α
V
REG-30α
V
REG-31α
For test
00 001 1
00 010 2
11 101
11 110
11 111
29
30
31
Electronic Control Data
Status V
EV
D7 D0
RAM AddressFunction
* : Unused
α
: α=VREG/95 (1/4biased)
Note: Do not use address 29H as it can be used for IC chip test only.
***
***
***
***
***
***
*****
. . . . . . . . . . . . . . .
LED Register Set Value
TIM2 LED2
Output Status (XLE1, XLE2)
TIM1 LED1
0 0 XLE = High impedance
0 1 XLE = Low
1 0 Keeps XLE low approximately 15 sec
after input of Display ON command.
1 1 XLE = Low
Note: When this function is used, minimize power supply and power
cable impedance to avoid IC misoperation due to large current.
LED Register Data
Function RAM Address
D7 D3 D2 D1 D0
LED ON/OFF 2AH ✽✽ ✽✽TIM2 TIM1 LED2 LED1
Timer
✽ : Unused