The Hung-Chang DSO-2100 is a parallel port PC oscilloscope sold back
in 1999 under brand names like Protek and Voltcraft.
This inital version of the driver has the following limitations:
- Hardcoded calibration values. All parameters are set to 50%.
- No support for auto triggering
- No support for TV sync trigger modes
- No support for the "scroll acquisition" mode
In scroll acquisition mode the device behaves more like a multimeter
and reports the current voltage of a probe on request. While in this
mode the sample rate is limited by the parallel port interface, it is
the only way to capture both channels at the same time (well, sort of).
Calibration would need auto triggering. The calibration values are very
temperature dependent and the device takes literally hours to reach its
final temperature. Every vdiv setting needs its own set of calibration
values. Without hardware modifications, the calibration settings wear
of in less than a second while waiting for a trigger because the
capacitors storing those values are not recharged in state 0x21.
This is set to | (or left empty) by SR_PROG_MAKE_ORDER_ONLY for
portability reasons, since not all Make implementations support
order-only prerequisites.
This is intended to make people notice when libusb is too old
for the new Windows code. However, this is not foolproof, since
the libusb version may be different at runtime.
Introduce new internal session API for changing the set of polled
file descriptors for an already installed event source. Use the
new API to apply changes to the USB poll FDs when requested to do
so by libusb. Doing so is necessary to make the generic USB code
work on Windows.
Provide SR_ARG_OPT_CHECK, a generalized variant of SRG_ARG_OPT_PKG
that can be used with custom check commands. Implement the latter
in terms of SR_ARG_OPT_CHECK.
There was a problem in scpi_serial.c in the scpi_serial_read_data()
function. Incoming data was written at the read position in the buffer,
although it should be written at the count position in the buffer.
This is another attempt at getting the mess that is libusb event
handling on Windows under control. Until libusb makes its HANDLEs
available for polling, we have no choice but to block while waiting
for libusb events. Since we do not want to force drivers to deal
with multi-threading issues, that means we have to block in the
session main loop.
Fortunately, it turns out that our drivers aren't using multiple
event sources, so it is actually possible to block the main loop
without disrupting too much. This also gets rid of the USB thread
on Windows. Thankfully, libusb does not seem to care that we are
now calling libusb_handle_events_timeout_completed() twice per
iteration: first a blocking call (with timeout) in the callback
wrapper, followed by the non-blocking call in the driver-supplied
callback.
Turns out that having one event source per libusb poll FD is
a bad idea. There is only a single callback for all poll FDs,
and libusb expects to be called only once per poll iteration,
no matter how many FDs triggered.
Also, they should all share the same timeout, which should get
reset on events from any polled FD. The new timeout handling made
this problem apparent, as it caused the callback to be invoked
multiple times on timeouts, once for each separate event source.
In order to fix this, change the implementation to allow for an
arbitrary number of poll FDs per event source. This number is
zero for timer FDs, one for normal I/O sources, and one or more
for libusb sources (Unix only).
Also, on Windows, do not get an additional timeout from libusb
in the event loop. This is only appropriate when polling the
libusb FDs directly, which we aren't doing on Windows.
Handle I/O sources and timer ("dummy") sources within the same
polling loop, so that both may be used together. Slightly change
the API to improve consistency: a timeout value of -1 now disables
the timeout, and 0 makes the source always time out immediately.
The "dummy" sources already behaved that way, although it wasn't
documented as such.
Make sure that I/O events are processed preferentially: Skip any
timeout callbacks if an I/O event occurred within the same poll
iteration. This applies to both timer/idle sources and timeouts
of I/O sources.
Do not create dummy GPollFDs for timer/idle sources. Instead,
split the sources array into an I/O section and a timer section,
and create corresponding GPollFDs only for the I/O section. Use
GArray to simplify the handling of the dynamic arrays.
Keep track of when source timeouts are due and properly compare
against accumulated elapsed time between invocations. This prevents
sources with short timeouts from blocking other sources with longer
timeouts indefinitely.
Looking at the g_poll() implementations for various systems, it
appears that on Windows the return value is 0 if the wait was
interrupted, and errno is never set. Also, the MacOS X wrapper
around select() does not clear revents on timeout.
To deal with these issues, check for EINTR only on Unices, and
assume revents to be invalid unless g_poll() returned a positive
value.
If the call to g_poll() in sr_session_iteration() fails, report
the error back to the caller. Do not treat EINTR as error though.
Check for session abort only if a source callback was actually
invoked, or at least once if none of the callbacks are invoked.
Stop checking for abort if the session has already been stopped,
just in case a callback sets abort_session again.
Also change the documentation to match the actual behavior.
In sr_session_iteration(), remove the inverted evaluation of the
block parameter if a USB source is present. This stops the deluge
of USB event callbacks due to the timeout always being zero.
Also, just for cleanliness, initialize the revents member of each
GPollFD instance to zero.
SWIG_init() returns void for Python 2.x and 'PyObject *' for Python 3.
Use an #if to handle both cases properly, otherwise the Python bindings
for either Python 2 or 3 will fail to build.
Python 3.x failure:
sigrok/core/classes_wrap.cpp: In function ‘PyObject* PyInit__classes()’:
sigrok/core/classes_wrap.cpp:59002:5: error: return-statement with no
value, in function returning ‘PyObject* {aka _object*}’ [-fpermissive]
return;
^
Python 2.x failure:
In file included from /usr/include/dirent.h:244:0,
from /usr/include/glib-2.0/glib/gdir.h:32,
from /usr/include/glib-2.0/glib.h:45,
from /usr/include/pygobject-3.0/pygobject.h:7,
from sigrok/core/classes_wrap.cpp:3179:
sigrok/core/classes_wrap.cpp: In function ‘void init_classes()’:
sigrok/core/classes_wrap.cpp:59002:12: error: return-statement with a
value, in function returning 'void' [-fpermissive]
return NULL;
^
Daniel Elstner
Daniel Glöckner
Uwe Hermann
Martin Ling
Soeren Apel
Bert Vermeulen
Martin Lederhilger