At high sampling rates and maximum channels we are not able to acquire
samples fast enough, even though frontends still think that samples
arrive on time. This causes visible shifts in frontend plots.
To compensate for the delay introduce the following workaround: check
if we are late (if any clock events have been missed) and resend the
last frame n times (n == number of missed clock events).
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Currently baylibre-acme uses a fake pipe as the input channel required by
libsigrok API and calls sleep() in the data acquisition callback to create
intervals between measurements.
Switch to a more elegant approach: use Linux' timerfd and set a periodic
timer equal to the sampling rate. Then read the data every time the timer
expires.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Opening a file has a cost (security, allocation, syscalls). The
read_sample() function always does an open/read/close sequence.
In order to optimize that, let's open the file at the moment the
acquisition starts, close it when the acquisition stops and make
read_sample() only lseek() to the beginning of the file and read
the value.
Signed-off-by: Daniel Lezcano <daniel.lezcano@free.fr>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
This was originally done as an optimization in combination with a list
reversal which has since been removed from the code. Thus, un-reverse
the channels so that the UI lists them in the correct order again.
When the import of gi.repository.GLib failed, we would get a NULL
pointer that we passed along without any checking. In this situation,
the entire program would crash with a segmentation fault, and no
message to indicate the problem.
When the import fails, abort the SWIG init and print a message. The
Python interpreter then prints out a backtrace, which can be useful
in tracking down the problem.
The Chroma 62000P series comes in various models with different
current and voltage capabilities. These are encoded in the *IDN
string, so just get them from there, rather than needing a profile
for every model.
All those options are currently applied only to power-supplies
but they could apply as well to electronic loads, except for the
fact that electronic loads channels are called inputs and not
outputs.
Also when you think about an SMU (or any kind of 4-quadrants
power-supply), their channels can both source and sink current,
so they can be considered as input as much as output.
Those SR_CONF_* are thus renamed so that they can be used in all
those situations.
For devices such as the HP 6632B the following invocation was failing due to
scpi_cmd(sdi, SCPI_CMD_SELECT_CHANNEL, ...) returning SR_OK_CONTINUE.
./sigrok-cli -d scpi-pps:conn=/dev/ttyUSB0:serialcomm=9600/8n1 --continuous
sr: session: sr_session_start: could not start an acquisition (not enough data to decide error status yet)
Failed to start session.
This patch only adds the needed infrastructure to control output
frequency in the same manner as output voltage or current limit. This
does require a new field in the channel_spec struct, for the sake of
symmetry.
This makes 'output_frequency' symmetrical with 'output_current' and
'output_voltage'. On a more fundamental level, there's no reason why
frequency should be treated as a discrete quantity, other than
"es51919 used it this way".
Only the capabilities which map directly to SCPI commands supported by
sigrok are implemented at this time. This is sufficient to control
the most often used functionality of this AC source
Some devices with more than one microcontroller report the firmware
version for each of them, giving us more than four tokens. When that
happens, sigrok aborts, even though it received a valid response.
This happens, for example with the Chroma 61604:
'Chroma ATE,61604,001060,1.25,1.34,1.20'
With gcc 5.1 released and defaulting to std=gnu11, the code will be compiled
according to different standards depending on the compiler version so we
should better specify explicitly what standard we are targetting.
C11 is now quite mature, it is supported in the just release Debian stable
(gcc 4.9) and also in old-stable (gcc 4.7), so there should be no reason to
use anything more ancient.
We also should have no reason to need any non-standard GNU extension.
So using only C11 + POSIX sounds like the best option right now.
Bartosz Golaszewski
Daniel Lezcano
Daniel Elstner
Uwe Hermann
Soeren Apel
Daniel Gröber
Carl-Fredrik Sundström
Alexandru Gagniuc
Jiří Pinkava
Marcus Comstedt
Aurelien Jacobs