KEPCO MST 488 Programmer - Manual (Page 28)

3-2
MST488-27 013004
3.2.1 STRING PARSING
When the MST 488-27 is in listen mode, strings are accepted. When the host controller sends
the last byte it can assert the EOI line to indicate the string is complete. The GPIB listener func-
tion automatically adds a LF to terminate the string input. The parsing software then processes
the string and if there are valid commands, the power supply is updated with the new control
input. Some GPIB host controllers do not have the ability to assert the EOI control line, however
the GPIB listener function will also terminate the string input when either a carriage return (0d
H
)
or Line Feed (0A
H
) character is received.
TABLE 3-2. IEEE 488 (GPIB) BUS COMMAND MODE MESSAGES
MNEMONIC MESSAGE DESCRIPTION COMMENTS
ATN Attention Received
DAC Data accepted Received or Sent
DAV Data Valid Received or Sent
DCL Device Clear Received
IFC Interface Clear Received
MLA My Listen Address Received
MTA My Talk Address Received
OTA Other Talk Address Received
RFD Ready for Data Received or Sent
SDC Selected Device Clear Received
SPD Serial Poll Disable Received
SPE Serial Poll Enable Received
SRQ Service Request Sent
UNL Unlisten Received
UNT Untalk Received
TABLE 3-3. IEEE 488 (GPIB) BUS DATA MODE MESSAGES
MNEMONIC MESSAGE DESCRIPTION COMMENTS
DAB Data Byte Received or Sent
END End Received or Sent
EOS End of String Received or Sent
RQS Request Service Sent
STB Status Byte Sent