SCD1284 INTEL [Intel Corporation], SCD1284 Datasheet - Page 69

• Manufacturer Part Number: SCD1284
• Description: IEEE 1284-Compatible Parallel Interface Controller with Two High-Speed Asynchronous Serial Ports
• Manufacturer: INTEL [Intel Corporation]

IEEE 1284-Compatible Parallel Interface Controller — CD1284
the selected character is transmitted immediately following the currently transmitting character and
any character in the Transmitter Holding register. This preempts any characters in the transmit
FIFO. If there are characters in the transmit FIFO, transmission resumes after the special character
is sent.
One important use of this command is that it allows the CPU to flow-control a remote without
having to wait for the transmit FIFO to empty before the flow control character is placed in it. This
is a special case different from the normal transmitter operation of the CD1284, in that the
character can be sent without waiting for a transmit service request. The only requirement is that
the transmitter must be enabled (interrupts need not be enabled).
Datasheet
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