The SCPI get routines may allocate memory for response data which
callers have to free after use.
This implementation is incomplete. The fluke-45 driver's context holds
a "global" copy of the most recently received response. While the data
is freed in the next receive call, one item remains allocated for the
driver's remaining life time. Which is considered non-critical.
Also moves an operator in a complex multi-line expression to a different
location to follow the project's style.
This addresses part of bug #1683.
Some of the SCPI getter routines allocate memory for response data which
callers need to free after use. Document this responsibility in more
places, and rephrase existing locations for consistency. See a word-diff
for the essence of the commit.
It's assumed that the separate paragraph in the function description is
better perceived than something that's hidden in the parameter or return
value discussion. Also reference the corresponding free routine by name
for callers' convenience (data types will differ among routines). Some
free routines can be called unconditionally, others require NULL checks
at the caller's.
Reported-By: Ralf <jr-oss@gmx.net>
Assign NULL early in those SCPI get routines which return allocated
memory to their callers. So that the return value is either a valid
pointer to memory or NULL regardless of the routine's exit code. This
simplifies call sites and increases robustness.
Opening a serial port involves two libserialport calls, while only the
second call's return value gets inspected. Check the lookup before the
open, too, and provide its details in a diag message.
When CSV import grabs channel names from the first line in the file then
the text strictly between column separators (a comma) was used. Which
resulted in channel names like " channel 1". Trim leading and trailing
space before unquote, to better fulfill most users' expectation. Users
still can quote the input data for special cases if desired.
The DPS devices default to a rather low UART communication bitrate. The
generous retrieval of more Modbus registers than strictly necessary for
the periodic acquisition of analog channel values and state tracking may
or may not be an issue.
Instrument all call sites in api.c to the device state gathering calls
such that the protocol.c side transparently can reduce the transfer
volume depending on which level of detail the caller may expect given
its current context. Under optimal circumstances this might cut the
traffic in half, which DPS devices may benefit from.
This commit adds the infrastructure to potentially reduce transfer
volume, but does not change behaviour. The "config" reasons may need
further partitioning if Modbus register access really turns out to be
a severe bottleneck. The API lends itself to that extension easily. The
approach which gets prepared in this commit needs to get runtime tested
by those who got access to the hardware.
The RD devices differ from DPS devices in their default communication
bitrate (115200), register content endianess (BE), and register set
layout (addresses for registers). In either case 16bit registers get
accessed by means of Modbus communication over a serial channel. The
interpretation of the registers' values mostly is the same as for DPS
devices once a register with the same meaning got identified. Device
identification includes a 32bit serial number which DPS devices appear
to not provide.
All other product features are the same, and map to identical sigrok
mechanisms. That's why re-using the rdtech-dps driver to add rdtech-rd
support is considered desirable. This implementation shares all code
"above" the raw register addressing and raw value interpretation. All
logical processing, configuration interface, state tracking and data
submission to the session feed, are shared among the different device
types.
Declare support for the RD6006, RD6012, and RD6018 models. Their specs
were taken from the 2020.12.2 instruction manual. The driver was tested
with an RD6006 device (firmware version 1.28). Unfortunately automatic
device detection is not possible or will not be reliable, which is why
users need to specify the respective model by picking one of the two
drivers. Within a driver variant the device identification and use of
the device are automatically dealt with.
The existing power supply driver for Riden DPS/DPH devices unfortunately
duplicated intimate details of modbus communication and register layout
including interpretation of raw register values across several source
files. Do separate the physical transport and the register layout and
register fields interpretation layers. This brings the driver in line
with the usual api.c and protocol.c arrangement of responsibilities, and
prepares the future addition of other similar devices.
Address a few style nits while we are here. Include <config.h> in all
source files, and alpha-sort include directives. Address minor data type
nits. Reduce indentation in code paths. Propagate more error codes.
Update comments which lagged behind the code, adjust grammer (eliminate
"actual" false friends). Eliminate a few magic numbers and redundancies,
switch to the more recent endianess aware byte stream reader API where
beneficial, to eliminate redundant offset math.
Other nits seem to have gone unnoticed before: The indices of all sigrok
channels were identical (all zero). Signed print formats were used for
unsigned data.
This implementation compiles, but wasn't runtime tested due to lack of
hardware. A rough estimate of transfer volume and transport throughput
suggests that the 10ms cycle time no longer can be kept, may end up
around 25ms (40 cycles per second). This can get avoided by adding more
code to tell the configuration requests, the acquisition start, and the
measurements grabbing during acquisition apart. It's assumed though that
the 10ms glib poll interval did not translate to such fast measurement
gathering. The firmware may typically provide data at lower rates anyway.
The generic source code may look overly complicated or redundant at
first glance, but compilers' generated code will greatly get optimized.
Simplified maintenance because of reduced cognitive load is considered
more important.
Improve readability by addressing the trivial style nits in the driver.
Break the channel list into two times eight instead of nine plus seven
items. Put braces around all branches if one of them has braces. Add
braces to multi line branches despite most of the branch just being a
comment -- it's still many lines. Break extra long text lines, adjust
the position of operators when single expressions span multiple lines.
Drop unnecessary parentheses around single variables and auto
incrementing pointer dereferences. Adjust whitespace especially for
pointer data types, and arith operators.
Eliminate packed structs in the construction and in the reception of
USB transfers, since these are rather non-portable. Use common support
for endianess aware access to byte streams instead. This unbreaks the
driver for MinGW builds, and increases portability and maintainability
on all other sigrok supported platforms.
[ gsi: adjust more locations, improve robustness, fixup style, reword message ]
The ezusb_upload_firmware() routine opens the USB device and selects the
current configuration. The specified value must match the previously read
configuration descriptor. This commit unbreaks the firmware download for
MinGW builds which link against libusb-1.0.20-rc3-event-abstraction-v4.
[ gsi: reworded commit message ]
The SCPI standard requires OPeration Complete command,
but some Owon meters do not implement it. This commit
makes the probe try OPC once, and if it gets no reply
it assumes it is not supported.
Try the identification command up to three times
if the device responds with 'Invalid Character.',
which can happen if the device has buffered part
of a command but not executed it.
Re-use HMP4000 options and channel groups, only keep separate channel
specs for HMP2000 devices. HMP2030 has three identical 32V/5A channels.
HMP2020 has one 10A channel and one 5A channel.
Specs published by R&S suggest that 10A channels support 0.2mA resolution,
while only 5A channels resolve to 0.1mA (up to 1A full scale, 1mA above 1A).
This fixes a bug where the channel group setting would not be overwritten in a
new run, but instead the channel group settings of both runs would be merged
together.
While the raw sample is the actual received data, the expanded sample is the
crucial data I as a developer am interested in seeing. At least if I assume that
the sample expansion works.
Introduce a DMM packet parser in src/dmm/ and register it with the
serial-dmm device driver. This adds support for the Meterman 38XR
multimeter.
[ gsi: style adjustment, raise awareness during maintenance ]