Internal Driver Resistors For Lcd Controller - Fujitsu F2MC-8FX Hardware Manual

24.2.1

Internal Driver Resistors for LCD Controller

with internal divider resistors, the power supply voltage for the LCD driver is generated
by the internal divider resistors (external divider resistors can also be connected).
Internal Divider Resistors
Internal divider resistors are included7. In addition, external divider resistors can be connected to
the LCD driving power pins (V1 to V3).
The internal and external divider resistors are selected by the driving power control bit in the
LCDC control register (LCDCC: VSEL). Setting the VSEL bit to "1" energizes the internal divider
resistors. To use only the internal divider resistors without connecting the external divider
resistors, set the VSEL bit to "1". Even when using internal split resistors, set the VE1 bits in LCDC
enable register 1 (LCDCE1) to "1". (When internal split resistors are used, the V3 to V1 pins cannot
be used as general-purpose output ports.)
The LCD controller stops upon transition to main stop or watch mode (STBC:TMD = 1) while
operation in main stop and watch modes is disabled (LCDCC:LCDEN = 0) with LCD operation
halted (LCDCC:MS1, MS0 = 00
To use the 1/2 bias setting, connect the V2 and V1 pins together.
Figure 24.2-2 shows an equivalent circuit with internal divider resistors used.
Figure 24.2-2 Equivalent Circuit with Internal Divider Resistors Used
*
V
3
V
2
V
1
LCDC enabled
VSEL
V to V : Voltages at V1 to V3 pins
1 3
*: Only for 3V products
).
B
P-ch 2R
N-ch
P-ch R
N-ch
P-ch R
N-ch
P-ch R
N-ch
N-ch
CHAPTER 24 LCD CONTROLLER
Vcc
V3
V2
Connect for
1/2 bias
V1
435