In the case of USB drivers, a driver's dev_acquisition_stop() cannot
simply remove its fd sources from the session and close its devices:
a USB transfer might still be underway, and it needs to be finished
(and its memory freed) properly.
An sr_dev_inst->status value is added: SR_ST_STOPPING, which should
be set when the driver's dev_acquisition_stop() is called, and acts
as a marker for the USB event handler to wind up its operations.
In order for dev_acquisition_stop() to be able to set the sdi status,
however, it needs to be unconstified.
- Default to 1MHz.
The default sample rate is the lowest frequency (100Hz),
but it takes a very long time until 128K memory is full.
- Fix the 1MHz setting.
- Use samplerate list.
- Fix 10MHz frequency.
- Fix trigger.
- Change the size of memory according to the number of samples.
- Add pre-trigger (capture ratio) setting.
- Fix the first acquisition after power on.
Move sr_usb_connect() and sr_usb_open() to hardware/common/usb.c in a
slightly more generic form and add more error checks and logging.
Let genericdmm use the new/moved functions.
Merge parts of the tekpower-dmm code (the chip of the TekPower
TP4000ZC seems to be an FS9721_LP3 too) and rework parts of the functions.
Adapt the tekpower-dmm and uni-t-dmm code accordingly.
So far, it seems we can make this work with just hw_init() needing to
be subdriver-specific (it will point 'di' to the respective per-subdriver
entry), the rest of the API functions can then use a strcmp() on di->name to
learn which subdriver they belong to.
The 'uni-t-dmm' driver/directory will not appear as a "driver" to
frontends anymore, it's just an internal thing.
The frontends will see a uni-t-ut61d and voltcraft-vc820 driver now,
with the correct names and parsers etc. attached to them.
This is not fully finished yet, but it's a start (and works mostly):
$ sigrok-cli -D
The following devices were found:
UNI-T UT61D with 1 probe: P1
Voltcraft VC-820 with 1 probe: P1
$ sigrok-cli --driver voltcraft-vc820 -D
The following devices were found:
Voltcraft VC-820 with 1 probe: P1
$ sigrok-cli --driver uni-t-ut61d -D
The following devices were found:
UNI-T UT61D with 1 probe: P1
# Now attaching a UNI-T UT61D device via USB.
$ sigrok-cli --driver uni-t-ut61d --samples 3 -O analog
P1: -0.017800 V DC
P1: -0.017600 V DC
P1: -0.017700 V DC
# Now attaching a Voltcraft VC-820 device via USB instead.
$ sigrok-cli --driver voltcraft-vc820 --samples 3 -O analog
P1: -0.319200 V DC
P1: -0.319300 V DC
P1: -0.319300 V DC
The Fortune Semiconductor FS9721_LP3 and FS9721B/Q100 DMM chips are very
similar and the protocol looks identical.
Tested on a Voltcraft VC-820 (FS9721_LP3) with the uni-t-dmm driver
(needs some small changes, tbd).
Uwe Hermann
Bert Vermeulen
Toshiaki Yoshida
Alexandru Gagniuc