The automatic selections of the measured quantity and equivalent circuit
model are more part of the configuration of the meter than attributes
of the measurement result. To reflect this, model them as config keys
instead of mqflags. This allows a driver that supports remote control to
implement 'set' method for them and has the additional benefit of saveing
two flag bits.
If the number and specs of the device's channels are not static, i.e.
need to be probed, this facility is needed.
Initially this will be used for the Philips PM2800 series, where only
the model returned by *IDN? is needed. However this could also be used
to do actual discovery with vendor-specific SCPI commands.
At least the Rigol DP800 series trigger the beeper when changing
channels remotely. Which gets rather annoying when doing acquisition
on three channels as fast as you can.
Add a driver for the DER EE DE-5000 LCR meter. This meter is based on
the Cyrustek ES51919/ES51920 chipset and communicates with the host
computer via an optional connectivity kit.
The kit uses an optoisolated unidirectional link to connect to the
meter and an USB cable on the host side. Internally the connection is
using the FTDI FT232R USB UART chip i.e. from the host computer point
of view the meter is connected into an RS-232 serial port.
This driver implements just a thin shim layer for registering the
driver and uses the es51919 module for all the actual work.
Add a protocol decoder for the Cyrustek ES51919 LCR meter chip.
This chipset (together with ES51920 front-end) is supposedly used
by multiple different portable LCR meters including at least
DER EE DE-5000, Yihua V&A VA520, Mastech MS5308, Uni-T UT612,
CEM DT-9935 and various OEM rebadges of them.
The communication protocol seems to be implemented on the Cyrustek
chip itself so all the different models are expected to use the
same protocol if they implement a host connection. Unfortunately
the protocol is not available in the public documentation of the
chipset, so this implementation is based on reverse engineering it
from traffic captures.
The actual connection between the meter and the host computer may be
different from meter to meter even when based on the same chip. This
module implements a decoder for the protocol and some common helper
functions for interfacing with the meter via an RS-232 serial port.
This calculates a proper timeout value for blocking writes on the
given serial port, for the given number of bytes. Timeout is based
on a fixed 10ms OS overhead, baud rate, data bits and stop bits.
Set this new parameter to 0 (no timeout) at every call site. This is
consistent with previous behaviour, so cannot cause any regressions.
Waiting forever for a serial operation is clearly always wrong. Without
specific knowledge of each device and driver however, I can't choose
appropriate timeouts for each call. The maintainers of these drivers
will need to do so, and also add appropriate handling of timeouts.
When this commit is merged, a bug should be entered for each driver
that is touched by it.
Bert Vermeulen
Janne Huttunen
Jens Steinhauser
Soeren Apel
Martin Ling
Uwe Hermann
Aurelien Jacobs