Rockwell Automation 6008-SI IBM PC I/O SCNNR 6008-SI - Manual (Page 96)

Chapter 8
Block Transfer
8-6
bt_read, bt_write
Use this routine to initiate a read or write BT. These macros compile as
references to bt_que, but save typing one argument.
Calling sequence:
status = bt_read(
address, &packet
);
or
status = bt_write(
address, &packet
);
Arguments:
same as the last two of bt_que above.
Returned values:
same as for bt_que above.
The factors affecting the time to empty the scanner’s BT queue are as
follows. They are roughly in descending order of importance.
The number of BTs queued to the same adapter. (Note: A single
adapter, containing more than eight slots and using single slot
addressing, appears to the scanner as two distinct adapters. In this case,
the lower eight slots belong to the first apparent adapter.)
The number of BTs queued to the same module.
The number of times an adapter appears in the scanner’s scan list.
The length of the scanner’s scan list.
The number of words of BT data to be exchanged.
The baud rate.
Time to
Completion