3M Touch Screen USB Resistive Controller SC500, Справочное руководство

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SC500 USB Controller Communications 23
3M Touch Systems Proprietary Information
Figure 2. Calibration Target Locations
*
The coordinates are in video terms, with the origin (0, 0) in the upper left corner of the screen. Examples from the
controller’s perspective, however, place the origin at the lower left corner of the screen (numbers in brackets). The
controller outputs 0 to 64K on both axes independent of display screen resolution.
Get Feature – Get Status
This is a request to send information that indicates the status of the controller. Among
the uses for this request are determining whether there were any power on check
errors determining whether the last request was completed successfully.
The response to the reset request is sent before the request completes. Polling (via the
status request) is then used to check the completion of those requests.
Table 14. Controller Status
Offset Field Size Value Description
0 bmRequestType 1 0xA1 Host to device
1 bRequest 1 0x01 Get Report
2 wValue 2 0x0306 03 = Feature
06 = Feature Report ID
4 wIndex 2 0 Always 0
6 wLength 2 8 Always 8
Table 15. Data Stage (controller response)
Offset Field Size Value Description
0 bReport ID 1 0x06 Feature Report ID
1 bPOCStatus 1 0xXX Power On Check Status
2 bCmdStatus 1 0xXX Status of last command
3 bTouchStatus 1 0xXX Finger Up/Down
4 bAsynchReports 1 0xXX 0x00 = asynchronous output off
0x01 = normal output
5 Not used 3 0 Not used
(0, 767) [0, 0]* [64k,0]*
Upper Right Calibration Target
X = 1023 – (1024 x 1/8) = 1023 – 128 = 895
Y = 0 + (768 x 1/8) = 0 + 96 = 96
Lower Left Calibration Target
X = 0 + (1024 x 1/8) = 0 + 128 = 128
Y = 767 - (768 x 1/8) = 767 - 96 = 671
(
1023, 0) [64K, 64k]*
(128, 671)
(895, 96)
0,0