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EPICS Workshop 2003 Dirk Zimoch 1
StreamDevice 2.0
A Multi-Purpose Character Driver
for EPICS 3.14
EPICS Workshop 2003 Dirk Zimoch 2
What´s cool
• Protocol controlled character I/O
• Support new devices by easy configuration
• Modular design allows to support– any record type (with device support)– new I/O hardware– exotic data formats– user defined functions
EPICS Workshop 2003 Dirk Zimoch 3
What´s new
• Using R3.14 OSI libraries– can run on a PC
• Using C++– modules with well-defined interfaces– plug in your own modules
• New protocol features– exception handlers– pre/post processing
EPICS Workshop 2003 Dirk Zimoch 4
Applications
• GPIB devices
• Serial line devices
• Network devices
• Logging to files
• Console I/O
• Client/Server Applications
EPICS Workshop 2003 Dirk Zimoch 5
Protocol File
• Plain text configuration
• One file per device type
• One protocol per function
• Simple commands– in string;– out string;– wait timeout;– event timeout;
EPICS Workshop 2003 Dirk Zimoch 6
I/O Formatting
printf/scanf-like format strings
• standard formats (%f, %d, %s, …)
• additional formats– %b binary (ASCII 0 and 1)– %r raw (two´s complement number)– %D BCD– %{…|…} enumeration
• user defined (exotic) formats
EPICS Workshop 2003 Dirk Zimoch 7
Exception Handlers
Do something special in a special situation
• onError– when input doesn’t match
• onReplyTimeout– when device doesn’t answer
• onInit (not really an exception :-)– when processed during initialisation
EPICS Workshop 2003 Dirk Zimoch 8
Protocol Examples
terminator = CR LF;
get_freq {out "FREQ?"; in "FREQ %f HZ";}
set_freq {out "FREQ %f HZ";
onInit {out "FREQ?"; in "FREQ %f HZ";} }
generic_read {out "%s"; in "%39c";}
# parameter \$1: switch number
set_switch {out "SW \$1 %{OFF|ON}";}
# exotic formats (..!!...!..!)
get_status {out "ST"; in "%11B.!";}
EPICS Workshop 2003 Dirk Zimoch 9
I/O Link
Record link INP or OUT contains
• Name of I/O channel (bus)
• Name of protocol file and protocol
• Protocol parameters (optional)
• I/O-hardware dependent parametersfield (DTYP, "stream")field (OUT, "@gpib1 mydevice set_switch(2) 7")
channel filename protocol protocol parameter
I/O parameter
EPICS Workshop 2003 Dirk Zimoch 10
Pre/Post Processing
Apply user defined functions to output/input
• checksumsout checksum("value %f");in verify("%20c" 0 skip);
• encryptionout "password " scramble("%s");
• additional informationout date("\%H:\%m:\%s") " X = %f";
EPICS Workshop 2003 Dirk Zimoch 11
Work in Process
• Support of new asynDriver– standardised character driver interface
• Implementation of new protocol features
• Debugging
• Documentation
Release this summermailto: [email protected]
