DocID024597 Rev 3 665/1693
RM0351 Liquid crystal display controller (LCD)
690
Figure 157. 1/2 duty, 1/2 bias
22.3.4 Segment driver
The segment driver block controls the SEG lines according to the pixel data coming from the
8 to 1 mux driven in each phase by the common driver block.
In the case of 1/4 or 1/8 duty
When COM[0] is active, the pixel information (active/inactive) related to the pixel connected
to COM[0] (content of the first two LCD_RAM locations) goes through the 8 to 1 mux.
The SEG[n] pin n [0 to 43] is driven to V
SS
(indicating pixel n is active when COM[0] is
active) in phase 0 of the odd frame.
The SEG[n] pin is driven to V
LCD
in phase 0 of the even frame. If pixel n is inactive then the
SEG[n] pin is driven to 2/3 (2/4) V
LCD
in the odd frame or 1/3 (2/4) V
LCD
in the even frame
(current inversion in V
LCD
pad) (see Figure 154).
In case of 1/2 bias, if the pixel is inactive the SEG[n] pin is driven to V
LCD
in the odd and to
V
SS
in the even frame.
When the LCD controller is disabled (LCDEN bit cleared in the LCD_CR register) then the
SEG lines are pulled down to V
SS
.
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