PXD10RM Datasheet, PDF (819/1332 Pages) Freescale Semiconductor, Inc – PXD10 Microcontroller

No remapping: Frontplanes FP[39:0] and BP[3:0] will stay the same, because condition n>=44 is
not fulfilled.
22.5.7 LCD Bias and Modes of Operation
The LCD64F6B driver has seven modes of operation:
• 1/1 Duty (1 backplane), 1/1 Bias (2 voltage levels)
• 1/2 Duty (2 backplanes), 1/2 Bias (3 voltage levels)
• 1/2 Duty (2 backplanes), 1/3 Bias (4 voltage levels)
• 1/3 Duty (3 backplanes), 1/3 Bias (4 voltage levels)
• 1/4 Duty (4 backplanes), 1/3 Bias (4 voltage levels)
• 1/5 Duty (5 backplanes), 1/3 Bias (4 voltage levels)
• 1/6 Duty (6 backplanes), 1/3 Bias (4 voltage levels)
The voltage levels required for the different operating modes are generated internally based on selected
reference voltage. If VLCD as reference selected, changing VLCD alters the differential RMS voltage
across the segments in the ON and OFF states, thereby setting the display contrast.
The backplane waveforms are continuous and repetitive every frame. They are fixed within each operating
mode and are not affected by the data in the LCD RAM.
The frontplane waveforms generated are dependent on the state (ON or OFF) of the LCD segments as
defined in the LCD RAM. The LCD driver hardware uses the data in the LCD RAM to construct the
frontplane waveform to create a differential RMS voltage necessary to turn the segment ON or OFF.
The LCD duty is decided by the DUTY bits in the LCD Control Register (LCDCR). The number of bias
voltage levels is determined by the BIAS bit in the LCDCR. Table 22-29 summarizes the Multiplex modes
(duties) and the bias voltage levels that can be selected for each multiplex mode (duty). The backplane pins
have their corresponding backplane waveform output BP[m-1:0] in high impedance state when in the OFF
state as indicated in Table 22-29. In the OFF state the corresponding pins BP[m-1:0]can be used for other
functionality.
Table 22-29. LCD Duty and Bias
Duty
LCDCR Register
DUTY
Backplanes
Bias Level
BP5 BP4 BP3 BP2 BP1 BP0 BIAS=0 BIAS=1
1/1
000
OFF
ON
1/1
1/2
001
OFF
ON
1/2
1/3
1/3
010
OFF
ON
1/3
1/4
011
OFF
ON
1/3
1/5
100
OFF
ON
1/3
1/6
101
ON
1/3
1/6
110
ON
1/3
1/6
111
ON
1/3
Freescale Semiconductor
PXD10 Microcontroller Reference Manual, Rev. 1
Preliminary—Subject to Change Without Notice
22-33