98000332621

3M Touch Systems, Inc. Proprietary Information – TSD-29087 Rev D

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>

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

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).

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

<SOH>Command<CR>

Receiving Responses from the Controller

After executing a command, the controller returns a response or acknowledgment to the

terminator in the following format:

<Header>Command Response<Terminator>

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

Systems terminal emulator key sequences. The format of controller responses varies

3M Touch Systems, Inc. Proprietary Information – TSD-29087 Rev D

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

The command response, which always follows the header, is a range of ASCII characters

Another standard response is 1 (ASCII character ‘one’ or 31 hexadecimal). In most

cases, this response indicates the command failed. The controller received an invalid

command that it could not execute.

Some possible reasons for a command failure include:

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

return CR. The hexadecimal code for the ASCII CR control character is 0D hexadecimal.

The value returned in the response will be the ASCII control character for a carriage

return, displayed on the screen as the cursor moving to the next line.

header, the response, and a terminator as follows:

Developers may use this information when writing touch applications, developing

custom drivers or touch configurations, or testing their touch systems. Developers can

use firmware commands to initialize the controller, select operating modes, specify data

formats, and execute diagnostic functions.

Most touch systems users do not have to use firmware commands to use their touch

systems. For example, users can use 3M™ MicroTouch™ Software to calibrate the

sensor or to determine the controller type and firmware version.

3M Touch Systems, Inc. Proprietary Information – TSD-29087 Rev D

Caution: This document assumes you are familiar with firmware commands and how to

use them. Executing some commands may alter the performance of your touch system

and render it inoperable. You should be aware of the results before executing any

<CTRL> A to enter the start of header.

Table 5 Firmware Commands for EX Serial Controller Development

Code

Description

CX Initiates an interactive 2-point calibration.

CR Collects the raw X and Y coordinates before normal scaling,

linearization, and filtering process.

Z Queries the controller and waits for a response.

OI Identifies the controller type and the firmware version.

Ppds[

b]

Lets you adjust the communication parameters (parity, data

bits, and stop bits) of the controller.

controller to stop sending data, and recalculates the

environmental conditions.

parameters. Note: the serial port is reset to N81 format tablet