Carrol Touch TouchSystems CarrollTouch Prog, Programmer'S Manual

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CARROLL TOUCH Appendix D - CTKERN Function Reference
Touch System Programmer’s Guide D-21
The buffer size value passed in
CX
is the maximum number of bytes
that the CTKERN driver writes to the report buffer. If the number of
report bytes is greater than this value, the excess bytes are discarded. If
the touch system does not respond to the command with a report within
a set time, the function returns with 00 in
CX
, indicating that a timeout
occurred and no report bytes were transferred.
The report buffer should be at least 64 bytes long. Since the CTKERN
driver can transfer a maximum of 512 bytes to the report buffer, the
maximum report buffer size necessary is 512 bytes.
No touch data is processed while this command is processed. The actual
algorithm used in this command is:
1. Disable TAPI driver event handler.
2. Send command.
3. Start timeout counter.
4. If the report comes back, transfer it to the report buffer and enable
the TAPI driver event handler.
If the report does not come back (timeout), indicate timeout and
enable the TAPI driver event handler.