Samsung C8278X User Manual

A LCON is located in set 1, bank 1, at address E0H, and is read/write addressable using Register addressing 
mode. It has the following control functions. 

•  LCD duty and bias selection 
•  LCD clock selection 
•  LCD display control 
•  Internal/External LCD dividing resistors selection 

The LCON register is used to turn the LCD display on/off, to select duty and bias, to select LCD clock and control 
the flow of the current to the dividing in the LCD circuit. Following a RESET, all LCON values are cleared to "0". 
This turns off the LCD display, select 1/4 duty and 1/3 bias, select 64Hz for LCD clock, and Enable internal LCD 
dividing resistors.   

The LCD clock signal determines the frequency of COM signal scanning of each segment output. This is also 
referred as the LCD frame frequency. Since the LCD clock is generated by watch timer clock (fw). The watch 
timer should be enabled when the LCD display is turned on. 

 

LCD Control Register (LCON)

E0H, Set 1, Bank 1, R/W

.7

.6

.5

.4

.3

.2

.1

.0

MSB

LSB

Internal LCD dividing register enable bit:
0 = Enable internal LCD dividing resistors
1 = Disable internal LCD dividing resistors

Not used for S3C8275X/C8278X/C8274X

LCD duty and bias selection bits:
000 = 1/4 duty, 1/3 bias
001 = 1/3 duty, 1/3 bias
010 = 1/3 duty, 1/2 bias
011 = 1/2 duty, 1/2 bias
1xx = Static

LCD display control bit:
0 = Turn display off
      (Turn off the P-Tr)
1 = Turn display on
      (Turn on the P-Tr)

LCD clock selection bits:
00 = fw/2

9

 (64 Hz)

01 = fw/2

8

 (128 Hz)

10 = fw/2

7

 (256 Hz)

11 = fw/2

6

 (512 Hz)

NOTES:
1.    "x" means don't care.
2.

When 1/2 bias is selected, the bias levels are set as V

LC0

, V

LC1

(V

LC2

), and V

SS

.