HD66108 Datasheet, PDF (32/60 Pages) Hitachi Semiconductor – (RAM-Provided 165-Channel LCD Driver for Liquid Crystal Dot Matrix Graphics)

HD66108
4.3 LCD Driving Voltage Setting
There are 6 levels of LCD driving voltages ranging from V1 to V6; V1 is the highest and V6 is the
lowest. As shown in Figure 20, column output waveform is made up of a combination of V1, V3, V4, and
V6 while row output waveform is made up of V1, V2, V5, and V6. This means that V1 and V6 are
common to both waveforms while mid-voltages are different.
To accommodate this situation, each block of the HD66108T is provided with power supply pins for mid-
voltages as shown in Figure 21. Each pair of V1R and V1L and V6R and V6L are internally connected
and must be applied the same level of voltage. Block B is fixed for column output and must be applied
V3 and V4 as mid-voltages. The other blocks must be applied different levels of voltages according to the
function of their LCD driving output pins; if the LCD driving output pins are set for row output, VMHn
and VMLn must be applied V2 and V5, respectively, while they must be applied V3 and V4,
respectively, if the pins are set for column output (n = 1 to 3).
Table 3 Relationship between FCR Settings and LCD Driving Voltages
Control Register (FCR)
LCD Driving Voltage Pins
ROS4 ROS3 Mode
VIR/VIL V3 V4 VMH1 VML1 VMH2 VML2 VMH3 VML3 V6R/V6L
0 0 165-column V1
0 1 65-row (R) V1
1 0 65-row (L/R) V1
1 1 33-row (R) V1
V3 V4 V3 V4 V3 V4 V3 V4 V6
V3 V4 V3 V4 V2 V5 V2 V5 V6
V3 V4 V2 V5 V3 V4 V2 V5 V6
V3 V4 V3 V4 V3 V4 V2 V5 V6
65-row (R): 65-row-output mode from the right side
65-row (L/R): 65-row-output mode from the left and right sides
33-row (R): 33-row-output mode from the right side
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