Asynchronous Serial Communications Programmer's Reference Manual (32022-90052)

Chapter 8 185
Intrinsics Reference
FCONTROL(26, 27)
being taken. No carriage return or linefeed is sent to
the terminal following a binary read. On writes, all
carriage control directives are ignored. Binary editing
mode is initially disabled by default.
Unlike most FCONTROL calls, binary mode does not
actually take effect until a read is posted to the device
following the FCONTROL call. If you are setting binary
mode for both reads and writes you should post a 0-byte
read immediately after the call to make sure binary
mode is set.
Because no special character processing occurs in
binary mode, any ASCII DC3 (XOFF) character passed
in the data will be echoed to the terminal, and the
terminal will be suspended as if an XOFF were sent
from the DTC. This problem can be avoided by calling
FCONTROL(13) to disable character echoing prior to
entering binary mode. Alternatively, you can turn off
XON/XOFF flow control at the terminal by sending the
appropriate escape sequences. You should be aware,
however, that disabling flow control may result in data
being lost.
Binary editing is useful for transferring 8-bit data to
and from a terminal. Because all 8 bits are considered
to be data, binary editing is not compatible with parity
checking, and parity must be disabled. In addition,
since no special character processing is possible in
binary mode, it cannot be used for block mode transfers.
In session mode, system break restores standard
editing at the terminal. If :RESUME is entered following
the break binary mode will be restored when the first
read is posted following the :RESUME. FCONTROL(26)
must be called to disable binary editing.
Binary reads are terminated by byte count, read
timeouts, and error conditions. CCE status is returned
for reads terminated on the byte count as specified in
the FREAD, READ, or READX call. CCL status will be
returned on timeouts and errors. Reads terminated on
timeout will return data entered before the timeout
occurred. For reads terminated on error, no data will be
returned.
Condition Codes
CCE Request granted.
CCG Not returned by this intrinsic.
CCL Failed due to an error.