PyTrbNet

This is a Python package wrapping libtrbnet.so from trbnettools. It allows accessing trbnet registers from Python.

The package comes with two additional features:

• XmlDb support. Allows to query registers by their name as specified in the corresponding xml file.
• PCASpy-based EPICS IOC providing TrbNet register status information to the EPICS detector control system.

Installation

This package can be installed from the Python Package Index via:

pip install trbnet

Configuration / Setup

As this Python package depends on the shared library libtrbnet.so for the communication with TrbNet, its location needs to be provided. This can be done by setting the environment variable LIBTRBNET.

libtrbnet.so in turn requires the environment variables DAQOPSERVER (if talking to TrbNet via a trbnetd daemon) or the IP of a TRB Board: TRB3_SERVER (if talking to TrbNet directly).

A fourth environment variable XMLDB comes into play, if the xmldb capabilities of this Python package are to be used. It should point to the location of the xml-db for your system.

Those environment variables can also be set from within Python with their lowercase variants libtrbnet, daqopserver, and trb3_server upon instantiating the TrbNet() class.

Here's an example using environment variables in the shell:

# Setting the relevant environment variables
export LIBTRBNET=/local/gitrepos/trbnettools/trbnetd/libtrbnet.so
export DAQOPSERVER=jspc55.x-matter.uni-frankfurt.de:1
export XMLDB=/local/gitrepos/daqtools/xml-db/database

# example call to get the value in the compile time
# register for all reachable TRBs:
trbcmd.py xmlget 0xffff TrbNet CompileTime

# With the environment variables set, you could also
# run Python and instantiate TrbNet(). It would
# pick up the settings from the exported variables.

or by setting the variables from within Python:

import os
from trbnet import TrbNet

lib = '/local/gitrepos/trbnettools/trbnetd/libtrbnet.so'
host = 'trbnetd_host:8888'
t = TrbNet(libtrbnet=lib, daqopserver=host)
# 0x40 is the register address of CompileTime
t.register_read(0xffff, 0x40)

Usage with Python

To read the content of the register address 0x0 for all connected TrbNet boards (broadcast address 0xffff), do:

import os
from trbnet import TrbNet

t = TrbNet()

response = t.register_read(0xffff, 0x0)
for endpoint in response:
    print("endpoint 0x{:08X} responded with: 0x{:08X}".format(endpoint, response[endpoint]))

The TrbNet() class has the following methods:

• register_read(trb_address, reg_address)
• register_write(trb_address, reg_address, value)
• register_read_mem(trb_address, reg_address, option, size)
• read_uid(trb_address)
• Furthermore, multiple methods starting with trb_ (e.g. trb_set_address(uid, endpoint, trb_address)) can be called as they are inherited from the parent class _TrbNet.

Usage of the Terminal Utility trbcmd.py

The package comes with a simple command line utility called trbcmd.py. It is a Python counterpart for the trbcmd utility provided by trbnettools.

What it can do:

read register values

trbcmd.py r 0xffff 0x0

read memory (subsequent register addresses)

Read three registers starting at 0x8005 from all boards:

trbcmd.py rm 0xffff 0x8005 0x3 0x0

xml-db queries

Ask all TrbNet nodes (broadcast 0xffff) for the register value of CompileTime as set in TrbNet.xml:

trbcmd.py xmlget 0xffff TrbNet       CompileTime

Resources

• The TRB Website
• TrbNet Manual