3M C3266PW User's Guide download pdf (Page 41)

3M™ Multi-Touch Chassis Display User Guide 41

3M Touch Systems, Inc. Proprietary Information – TSD-39373B

3M Touch Systems recommends that the touch driver generate an interrupt as each packet

in the data stream arrives. Because touchdown and liftoff events are specially coded, your

software can generate mouse events that correspond to what the user is doing. This

enables instant feedback and prevents data loss.

Communicating with the Controller

This section provides information on sending firmware commands to the controller and

interpreting the responses that the controller returns.

The commands listed in Table 18 are those that 3M Touch Systems currently uses for

development. 3M Touch Systems recommends that you use only these commands for

3M™ PX serial controller development.

Commands to the controller are sent on the signal Receive Data (RXD) line as a serial

data stream. For each command it receives, the controller sends a response to the host on

the signal Transmit Data (TXD) line also as a serial data stream.

Sending Commands to the Controller

When you send a command to the controller, you must use the correct command format.

The general format of a command is as follows:

<Header>Command<Terminator>

Note: The following descriptions of header, command, and terminator, use 3M Touch

Systems terminal emulator key sequences. You may need to enter the sequence in a

different format, depending on your emulator.

The header is the first character in the command string and is the ASCII start-of-header

control character SOH. The hexadecimal code for the ASCII SOH control character is 01.

To start the command sequence, use the key combination Ctrl A (^A). If you are working

with an IBM PC compatible system, the Ctrl A key combination immediately returns an

ASCII ☺ character.

The command, which always follows the header, consists of ASCII uppercase letters and

numbers only (printable characters).

The terminator is the last character of each command string and is an ASCII carriage

return CR. An ASCII CR control character is 0D hexadecimal. To enter a carriage return,

ending the command sequence, use Enter or the key combination Ctrl M (^M).

This appendix lists each command as a string of ASCII control characters and printable

characters consisting of a header, the command, and a terminator as follows:

<SOH>Command<CR>

1 2 ... 36 37 38 39 40 41 42 43 44 45 46 ... 53 54

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3M C3266PW User's Guide Page 41