Specifications

CARROLL TOUCH Chapter 4 - Smart-Frame Protocol
Touch System Programmer’s Guide 4-13
Number of Processors Independence
Get_Error_Report (32H) causes an Error Report to be returned that
details the errors for each processor in the touch system. Use the
Get_Configuration_Report (33H) command to get a Configuration
Report that includes the number of processors in the touch system to
properly interpret this report. Do not hard wire the code that interprets
the Error Report to work with a specific number of processors.
Firmware Version Independence
Get_Firmware_Version_Report (34H) causes a Firmware Version
Report to be returned that lists firmware versions for various touch
system components. Do not hard wire the code that interprets the
Firmware Version Report to only work with a specific number of
version reports or a specific firmware version.
Frame Size Independence
If a software calibration and scaling program, as described in this guide,
is used, a change to a touch system with a different size frame simply
requires that the calibration program be run on the new touch system.
The frame size difference is reflected in the calibration parameters, and
the touch application or driver code itself does not need to be modified.
Do not hard wire the touch application or driver to a specific frame size,
since this requires the touch application or driver to be modified if a
different size frame is used.
Touch System Response Time
Independence
The amount of time required for a touch system to process a command
may vary, depending upon the model of the touch system. This, coupled
with the fact that there is no provision for software flow control in the
host-to-touch system direction, means that the input queue of the touch
system could overflow, causing commands to be missed if the touch
system is bombarded with commands at a faster rate than it can process
them. This usually occurs only when a long sequence of initialization
commands is issued at a high baud rate.
To prevent this overrun and loss of command characters:
1. Use a delay of approximately 10 milliseconds between commands
to allow the touch system time to process each command before
the next is sent.
2. Use a lower baud rate.