Specifications

Chapter 4 - Smart-Frame Protocol CARROLL TOUCH
4-8 Touch System Programmer’s Guide
HBC Hardware Reset Register
For touch systems that use the modular HBC, writing any value to the
HBC Hardware Reset Register (Base Address +2) resets the touch
system. This type of reset is equivalent to cycling the power to the touch
system.
Break (Firmware Detected)
For all touch systems that communicate serially, a break of at least
150ms resets the touch system. To send a break of 150ms, set the
Transmit Data (TD) signal to the “space” condition (positive voltage),
wait 150ms, 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, except that Clear To Send (CTS) is not affected if
hardware flow control was not enabled before the reset.
Reset (45H)
This Smart-Frame Protocol command resets everything. If the touch
system communicates serially and hardware flow control is enabled,
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/autoparity sequence by sending breaks. If hardware flow
control is disabled, Clear To Send (CTS) is not affected. This type of
reset is equivalent to cycling the power to the touch system, except that
the Clear To Send (CTS) is not affected if hardware flow control was
not enabled before the reset. Also, if the touch system communicates
serially but is set to use a fixed baud rate and parity (not
autobaud/autoparity), or if the touch system uses the HBC, the touch
system sends a Power Up Report (F1 FF) when it is ready to receive
commands.
In all cases, the touch system is ready to receive commands within one
second after the reset occurs. Touch applications must delay for one
second after resetting the touch system. In cases where a break is sent,
the one second time does not begin until the break is released.
Performing the Autobaud/Autoparity
Sequence
If you are using a touch system that communicates serially and is set to
use autobaud/autoparity, you must perform the autobaud/autoparity