StreamDevice 2.0

1
StreamDevice 2.0

• A Multi-Purpose Character Driver
• for EPICS 3.14

2
Whats 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

3
Whats 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

4
Applications

• GPIB devices
• Serial line devices
• Network devices
• Logging to files
• Console I/O
• Client/Server Applications

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

6
I/O Formatting

• printf/scanf-like format strings
• standard formats (f, d, s, )
• additional formats
• b binary (ASCII 0 and 1)
• r raw (twos complement number)
• D BCD
• enumeration
• user defined (exotic) formats

7
Exception Handlers

• Do something special in a special situation
• onError
• when input doesnt match
• onReplyTimeout
• when device doesnt answer
• onInit (not really an exception -)
• when processed during initialisation

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 OFFON"
• exotic formats (..!!...!..!)
• get_status out "ST" in "11B.!"

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 parameters
• field (DTYP, "stream")
• field (OUT, "_at_gpib1 mydevice set_switch(2) 7")

channel
I/O parameter
protocol parameter
filename
protocol
10
Pre/Post Processing

• Apply user defined functions to output/input
• checksums
• out checksum("value f")
• in verify("20c" 0 skip)
• encryption
• out "password " scramble("s")
• additional information
• out date("\H\m\s") " X f"

11
Work in Process

• Support of new asynDriver
• standardised character driver interface
• Implementation of new protocol features
• Debugging
• Documentation
• Release this summer
• mailto dirk.zimoch_at_psi.ch