Carrol Touch Modular Flat Panel Specifications download pdf (Page 48)

CARROLL TOUCH Chapter 4 - Smart-Frame Protocol

Touch System Programmer’s Guide 4-7

Touch System Initialization

To initialize a touch system that uses the Smart-Frame Protocol, take

the following steps:

1. Reset the touch system.

2. Perform the autobaud/autoparity sequence, if appropriate, then the

software reset command.

3. Check for any errors that may have been detected.

4. Set the desired reporting method and touch mode.

Details on each step are in the following sections.

Resetting the Touch System

The following methods may be used to reset the touch system. Be sure

to use a method that is appropriate for the touch system being used.

Power Cycle

This method resets everything. For touch systems that communicate

serially, Clear To Send (CTS) is deasserted (negative voltage) to

indicate that the touch system is busy until the touch system is ready to

accept commands. For serial touch systems that have their

communication parameters set to autobaud/autoparity, this occurs

when the touch system enters the autobaud sequence by sending breaks.

Dedicated Reset Signal

On some Smart-Frame systems, a dedicated reset signal line is present.

If present, this signal is on pin 8 of the 2 x 5 pin communication

connector that is on the frame. To reset the touch system, deassert this

pin by applying negative voltage for a minimum of 10 ms. This type of

reset is equivalent to cycling the power to the touch system. This signal

is not present on the modular RS-232 controller.

Break (Hardware Detected)

For touch systems that use the modular RS-232 controller, a break of at

least 400 ms resets the touch system. To send a break of 400 ms, set the

Transmit Data (TD) signal to the “space” condition (positive voltage),

wait 400 ms, and set the TD signal back to the “mark” condition

(negative voltage). For PC systems, the “Set Break” bit in the Line

Control Register of the 8250 USART chip is used to set and/or clear the

break condition. This type of reset is equivalent to cycling the power to

the touch system.

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Carrol Touch Modular Flat Panel Specifications Page 48