FUJITSU Semiconductor Controller MB89950/950A - Manual (Page 265)

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CHAPTER 12 LCD CONTROLLER/DRIVER
12.4.1 Output Waveforms during LCD Controller/Driver
Operation (1/2 Duty Ratio)
The display drive output is a multiplex drive-type two-frame a.c. waveform. In the 1/2
duty ratio mode, the only common outputs are COM0 and COM1. (COM2 and COM3 are
not used.)
■ 1/2 bias, 1/2 duty output waveform
The maximum potential difference exists between a segment output and the corresponding common output
when the segment (LCD cell) is turned on. Figure 12.4-2 "Output waveforms, 1/2 bias and 1/2 duty ratio
example" shows the output waveforms for the display RAM contents listed in Table 12.4-1 "Display RAM
contents example".
Table 12.4-1 Display RAM contents example
Segment
Display RAM contents
COM3 COM2 COM1 COM0
SEGn
− −
0 0
SEGn+1
− −
0 1
−: Not used