Fujitsu F2MC-8FX Hardware Manual page 452

CHAPTER 24 LCD CONTROLLER
Use of External Divider Resistors
As the V1 pin is connected to V
resistors, you can shut off the current flowing to the resistors when the LCD controller is halted by
connecting the V
external divider resistors used.
1) To connect the external divider resistors without being affected by the internal divider resistors,
you need to write "0" to the drive voltage control bit in the LCDC control register
(LCDCC:VSEL) to disconnect all the internal divider resistors. Write "1" to the V3 to V1 select
bits in LCDC enable register 1 (LCDCE1:VE1) so that the target ports can be used as power
supply pins to drive the LCD.
2) When the internal divider resistors are disconnected, writing a value other than "00
display mode select bits (MS1 and MS0) in the LCDC control register turns on the LCDC
enable transistor (Q1) and current flows in the external divider resistors.
3) Writing "00
transistor (Q1) and this stops the current flow in the external divider resistors.
Note:
The externally connected RX resistors depend on the LCD you are using. Select appropriate
resistances to match the LCD.
438
end of the divider resistors to the V1 pin. Figure 24.2-6 shows the states with
SS
Figure 24.2-6 States with External Divider Resistors Used
V to V : Voltages at V1 to V3 pins
1 3
" to the display mode select bits (MS1 and MS0) turns off the LCDC enable
B
(GND) internally via a transistor, when using external divider
SS
2R
V
3
R
V
2
R
V
1
R
LCDC enabled
Q1
Vcc
VR
V3
RX
V2
RX
V1
RX
" to the
B