3M M2256PW User Manual - Page 38

38 3M™ Display M2256PW User Guide where: Tt = Two ASCII characters that identify the controller type. AD Indicates the PX series of controllers Ffff = Four ASCII characters that indicate the features supported by the controller. **** Indicates no additional features configured Ss = Two ASCII characters that provide status information about the controller hardware. The two characters represent one byte. Each character is in the range 0 to 9 and A to F. Table 2 defines the meaning of each bit in the status byte. Each bit can be set to 1 or 0, where 1 = an error and 0 = no error. So a response of: 00 = No diagnostic errors (normal response) The PX running with no errors returns the following string: AD****00 The format includes two bitmapped ASCII hex status bytes. A "00" indicates no errors. Table 19 Bit Meanings in Status Byte Bit Description Notes 0 Not used 1 ROM_ERROR Code area checksum error 2 PWM Error Touch screen not connected or potential problem. 3 NOV_ERROR Parameter Block1 checksum error 4 HDW_ERROR Problem with ADCs 5 Not used 6 Not used 7 Not used Touch Data Format The format is a six byte packet that includes one status byte, four bytes of binary X,Y position data and a touch ID. The X,Y coordinates are 14 bits, providing a range of 0 to 16,383. The data is sent in the following format: 3M Touch Systems, Inc. Proprietary Information