Programming instructions

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Intermec Fingerprint 6.13 – Programmer's Guide
7. INPUT TO FINGERPRINT, cont'd.
Continued!
8. Background
Communication
Background communication means that the printer receives data on
an IN channel while the program runs in a loop. The data are stored
in a buffer, that can be emptied at an appropriate moment by the
running program, which then can use the data. Note that back-
ground communication buffers are not the same as the receive
buffers. Any input received on a communication channel is first
stored in the channel's receive buffer, awaiting being processed.
After processing, the data may be stored in the background commu-
nication buffer.
The following instructions are used in connection with background
communication:
COMSET Decides how the background reception will
work in regard of:
- Communication channel.
- Start character(s) of message string.
- End character(s) of message string.
- Characters to be ignored.
- Attention string that interrupt reception.
- Max. number of characters to be received.
ON COMSET GOSUB Branches the program execution to a subrou-
tine when background reception on a speci-
fied channel is interrupted.
COMSET ON Empties the buffer and turns on background
reception on the specified channel.
COMSET OFF Turns off background reception on the speci-
fied channel and empties the buffer.
COM ERROR ON Enables error handling on a channel.
COM ERROR OFF Disables error handling on a specified chan-
nel (default).
COMSTAT Reads the status of the buffer of a channel.
COMBUF$ Reads data in the buffer of a channel.
LOC Returns the status of the buffers in a
channel.
LOF Returns the status of the buffers in a
channel.
To set up the printer for background communication, proceed as
follows:
• Start by enabling the error handling for background communication
using a COM ERROR ON statement and specifying the communi-
cation channel you intend to use:
0 = "console:"
1 = "uart1:"
2 = "uart2:"/"rs485:"
3 = "uart3:"
4 = "centronics:"
☞ Memory and Buffers
Also see:
• Chapter 6.1