NXP Semiconductors MC9S08LG16, Reference Manual

Page: 187 / 373

Chapter 8 LCD Module (S08LCDLPV1)
MC9S08LG32 MCU Series, Rev. 5
Freescale Semiconductor 187
9.4.4.1.1 CPSEL: LCD Charge Pump or Resistor Bias Enable
The CPSEL bit in the LCDSUPPLY register selects the charge pump. When the charge pump is selected
(CPSEL = 1), V
LL1
, V
LL2
, and V
LL3
can be generated internally or V
LL1
and V
LL2
can be generated from
supplied V
LL3
.
When the charge pump is unselected (CPSEL = 0), V
LL3
must be supplied and V
LL1
, V
LL2
are generated
by a resistor bias network.
9.4.4.2 LCD Power Supply and Voltage Buffer Configuration
The LCD bias voltages can be internally derived from V
DD
, or externally derived from a voltage source
(must not exceed V
DD
) connected to V
LL3
. Table 9-19 provides a more detailed description of the power
state of the LCD module which depends on the configuration of the VSUPPLY[1:0] and CPSEL bits.
Table 9-19 shows all possible configurations of the LCD Power Supply. All other combinations of the
configuration bits above are not permissible LCD power supply modes and should be avoided.
Table 9-19. LCD Power Supply Options
LCD Operational State LCD Power Supply Configuration
VS
UPP
L
Y[1:0]
CPSEL
V
LL3
is driven internally for 5 V LCD Glass
operation.
Resistor Bias network enabled.
V
LL3
must equal VDD
For 5 V glass operation V
LL3
must equal 5 V.
Charge pump is disabled.
Resistor Bias network is used to create V
LL1
and V
LL2
.
01 0
V
LL2
connected to V
DD
internally for 3 or
5 V glass operation.
For 3 V glass operation V
DD
must equal 2 V.
For 5 V glass operation V
DD
must equal 3.33 V
Charge pump is used to generate V
LL1
and V
LL3
00 1
V
LL3
connected to V
DD
internally for 3 V or
5 V glass operation
For 3 V glass operation V
DD
must equal 3 V.
For 5 V glass operation V
DD
must equal 5 V.
Charge pump is used to generate V
LL1
and V
LL2
01 1
V
LL3
is driven externally for
3 V LCD Glass operation.
For 3 V glass operation V
LL3
must equal 3 V.
Charge pump is used to generate V
LL1
and V
LL2
11 1
V
LL3
is driven externally for 5 V LCD Glass
operation.
V
LL3
must equal V
DD
For 5 V glass operation V
LL3
must equal 5 V.
Charge pump is used to generate V
LL1
and V
LL2
11 1