BU21029GUL Datasheet, PDF (17/29 Pages) Rohm – 4-wire Resistive Touch Screen Controller

BU21029GUL
Table 11. 2-point Touch Coordinate Conversion Flow
step
operation
1
All the data is acquired and converted according to the procedure in p.16.
2
If required, a filter etc. will be processng the data.
3
If there is only 1-point touch detection, conversion ends.
4
2-point touch detection:
2-point touch is detected by comparing PX、PY and GH with a threshold.
If 2-point touch is not detected, conversion ends.
5
X-axis 2-point distance calculation 1:
Data is acquired from the distance conversion table using the maximum of 2 points
distance (PXMAX) determined beforehand.
The data is set to PRMX1.
6
X-axis 2-point distance calculation 2:
Data is acquired from the distance conversion table using PX.
The data is set to PRMX2.
7
X-axis 2-point distance calculation 3:
The 2-point distance X-axis (DX) calculated.
DX = 2048 * (PRMX2 / PRMX1)
8
Y-axis 2-point distance calculation 1:
Data is acquired from the distance conversion table using the maximum of 2 points
distance (PYMAX) determined beforehand.
The data is set to PRMY1.
9
Y-axis 2-point distance calculation 2:
Data is acquired from the distance conversion table using PY.
The data is set to PRMY2.
10 Y-axis 2-point distance calculation 3:
The 2-point distance of Y-axis (DY) calculated.
DY = 2048 * (PRMY2 / PRMY1)
11 ^{X-axis 2-point touch coordinate conversion:}
X-axis 2-point touch coordinate is converted from center position(X) and distance(DX).
X1 = X + DX
X2 = X - DX
12 ^{Y-axis 2-point touch coordinate conversion:}
Y-axis 2-point touch coordinate is converted from center position(Y), distance(DY) and
ghost value(GH).
When GH is greater than threshold.
Y1 = Y + DY
Y2 = Y - DY
When GH is less than threshold.
Y1 = Y - DY
Y2 = Y + DY
13 ^{2-point coordinate is generated and since they are not exact coordinates, if 2-point}
coordinates are required, they process offset etc.
14 Conversion is ends.
(*1)PXMAX is the value of PX when touching both ends of x-axis on touch screen.
(*2)PYMAX is the value of PY when touching both ends of x-axis on touch screen.
(*3)A coordinate is set to 4095 if it becomes over 4095 and to 0, if it becomes below 0.
Datasheet
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TSZ02201-0Y1Y0F300120-1-2
11.Nov.2013 Rev.002