Chapter 3. Service Precaution - Sharp UP-3301 Service Manual

CHAPTER 3. SERVICE PRECAUTION

1. Calibration
1. Calibration
The coordinates on the touch panel and those on the VGA display may
not match for the following reasons.
• The physical deviation between the touch panel and LCD display
• Variations in "electric resistance>coordinate" conversion on the touch
panel
Correction for such deviations is to perform the calibration.
2. Timing of starting calibration
Calibration is started in the following two cases:
– SRV reset/MRS –
1) When the touch panel is pressed:
Calibration is started when a PROGRAM reset/MRS is performed
with the touch panel pressed at the same time.
2) When no calibration has been performed:
Calibration is started when the calibration data held by the touch
panel controller is broken.
Note: Case 2 isn't performed if case 1 is performed prior to the second.
Calibration is also started when the EEPROM on the touch panel PWB
is replaced.
Note: If the touch panel unit is replaced for any reason such as a
repair, then start calibration, by following case 1).
3. Calibration specifications
1) The character text "Calibration Mode" is displayed.
2) If the touch panel is kept pressed, the machine waits for the finger
leaving the touch panel.
3) The character text "Touch these crosses" is displayed.
4) Entering correction mode
The command "Entering correction mode" is issued to the touch
panel controller.
At this step, the coordinate data of the four corners in the input area
are passed to the controller.
5) Correction points are displayed
The correction points are displayed.
All of the nine correcting points are displayed as follows using the
mark "+". The "+" mark is 18 by 18 dots with 2 dots thick.
VGA Display
18 dots
(16,14) (320,14)
18 dots
(16,240) (320,240)
(16,465) (320,465)
6) Correction points are input
Arbitrary correction points are input. Coordinate data corresponding
to its input are output from the touch controller. Note the data are
those of the initial coordinates. (Refer to the table below.)
The point from where the finger leaves the touch panel is defined as
the correction point input position (OFF position).
The data on the nearest correction point is checked, and if almost
appropriate, (regarding data of the initial coordinates, within +/-100
dots and +/-5mm in size) the command "correction data set" is
issued to the controller. When the panel is released and it is possi-
ble to correct the settings by touching the panel, changing the "+"
mark green.
If the input coordinates are very far from the correction point, it will
be neglected. If the command "correction data set" is terminated
normally, the mark "+" at the correction point turns black.
The input coordinate data are those of the initial coordinates, and
the relation to the correction points is as follows:
The data of the initial coordinates of correction points
393, 402
393, 2048
393, 3697
7) Step 6) is repeated for the nine correction points.
Correction is performed in an arbitrary order. At first all of the nine
points are displayed in white and they turn black as corrected.
8) After all of the points are corrected, the command "correction mode
end" is issued to the controller.
The maximum coordinates are (4096, 4096).
9) The display mode is returned to the text mode.
*If the power supply is turned off during correction, the following mes-
sages are displayed and all the steps are started over again.
Calibration failed.
Touch the panel to try again
Nine correction points are
displayed on VGA screen
Coordinates are obtained
from the touch panel controller
(624,14)
Coordinates are obtained
from touch panel controller
(624,240)
(624,465)
UP-3301US SERVICE PRECAUTION
– 9 –
2080, 402
2080, 2048
2080, 3697
Calibration flow
Correction mode
N
Panel pressed?
Y
Y
Panel pressed?
Correcting point>corrected
N
N
Not-yet corrected
point +/-100?
Y
Correction data set
3767, 402
3767, 2048
3767, 3697
Y
Correction error?
N
Correction point is thined
N
All of nine points
finished?
Y
Correction mode end