a-Si TFT LCD Single Chip Driver
240RGBx320 Resolution and 262K color
ILI9325
1. Gradient adjustment registers
The gradient adjustment registers are used to adjust the gradient of the curve representing the relationship
between the grayscale and the grayscale reference voltage level. To adjust the gradient, the resistance
values of variable resistors in the middle of the ladder resistor are adjusted by registers PRP0[2:0]/PRN0[2:0],
PRP1[2:0]/PRN1[2:0]. The registers consist of positive and negative polarity registers, allowing asymmetric
drive.
2. Amplitude adjustment registers
The amplitude adjustment registers, VRP0[3:0]/VRN0[3:0], VRP1[4:0]/VRN1[4:0], are used to adjust the
amplitude of grayscale voltages. To adjust the amplitude, the resistance values of variable resistors at the top
and bottom of the ladder resistor are adjusted. Same as the gradient registers, the amplitude adjustment
registers consist of positive and negative polarity registers.
3. Fine adjustment registers
The fine adjustment registers are used to fine-adjust grayscale voltage levels. To fine-adjust grayscale
voltage levels, fine adjustment registers adjust the reference voltage levels, 8 levels for each register
generated from the ladder resistor, in respective 8-to-1 selectors. Same with other registers, the fine
adjustment registers consist of positive and negative polarity registers.
Gradient adjustment
Amplitude adjustment
Fine adjustment
Figure 40 Gamma Curve Adjustment
Register Groups Positive Polarity Negative Polarity Description
Gradient
adjustment
PRP0 [2:0]
PRP1 [2:0]
VRP0 [3:0]
VRP1 [4:0]
KP0 [2:0]
KP1 [2:0]
KP2 [2:0]
KP3 [2:0]
KP4 [2:0]
KP5 [2:0]
PRN0 [2:0]
PRN1 [2:0]
VRN0 [3:0]
VRN1 [4:0]
KN0 [2:0]
KN1 [2:0]
KN2 [2:0]
KN3 [2:0]
KN4 [2:0]
KN5 [2:0]
Variable resistor VRCP0, VRCN0
Variable resistor VRCP1, VRCN1
Variable resistor VROP0, VRON0
Variable resistor VROP1, VRON1
Amplitude
adjustment
8-to-1 selector (voltage level of grayscale 1)
8-to-1 selector (voltage level of grayscale 8)
8-to-1 selector (voltage level of grayscale 20)
8-to-1 selector (voltage level of grayscale 43)
8-to-1 selector (voltage level of grayscale 55)
8-to-1 selector (voltage level of grayscale 62)
Fine adjustment
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Version: 0.35
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