Appendix B
Using the DMAmove and CDS-852 Adapter Code Instruments
©
National Instruments Corporation
B-9
852 Adapter CI Commands
The 852 adapter CI commands are interpreted by the CI itself and do not directly affect
the 852 module. If the adapter CI receives a word serial buffer that does not begin with
the
!!
character sequence, it assumes that the buffer is for the 73A-852 and writes the buffer
to the appropriate A24 register location. The CI command formats were designed to minimize
the possibility of conflict with the command sets of the various plug-in instruments that are
compatible with the 852 adapter. Because National Instruments has not had the opportunity
to study the command sets of all CDS plug-in instruments, you need to keep in mind the
possibility of conflict as you develop your applications.
The
!!A
and
!!B
commands set the CI read mode for compatibility with the CDS instrument.
Some CDS command responses are in ASCII format, while others are in binary format.
Refer to the appropriate CDS manual for the response format of a particular command.
The
!!A
command sets the adapter CI mode to be compatible with the ASCII response
format. If the expected response format is binary, use the
!!B
command to set the CI to
the binary read mode.
Two termination conditions can apply to reading data from the 73A-852. Depending upon
the 73A-852 configuration and the operation being performed, the 852 may terminate the
transmission of data with an end-of-string (EOS) character, or it may assert the END bit
(VMEbus data bit 8).
The
!!E
,
!!T
, and
!!t
commands configure the CI termination conditions. The EOS and
END bit termination conditions are independent; that is, you can configure the CI to terminate
a read from the 73A-852 on one condition, both conditions, or neither condition. In addition,
you can limit the maximum size of binary mode reads with the
!!S
command. Notice that
with binary responses, there can be no unique EOS character, so you should use the END
or transfer size conditions (not EOS) to terminate binary transfers. The default read mode
is ASCII. The default read termination condition is the EOS character <LF> (0Ah) with the
END bit set.
The
!!Q
command returns information about the CI settings (always to the serial port).
The
!!D
and
!!d
commands
control
the
printing
of
runtime debug information to the terminal
connected to the serial port.
