USB 2.0 on Picoscope 4424A

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phgphd
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Joined: Wed Jun 16, 2021 12:33 am

USB 2.0 on Picoscope 4424A

Post by phgphd »

Using Picoscope 7 PS4000A API with Picoscope 4424A on Ubuntu 22.04. When using USB3.0 connected to Picoscope I am able to successfully block capture data, but when using USB 2.0 I am getting following error:

GetValues failed: err = 37 ( 0x25 = Data is unavailable because a run has not been completed).

To do the block capture without a trigger, I use the following code for both USB 3.0 and 2.0:

// Halt Picoscope.
sts = ps4000aStop(mConfig.device);
// Restart Picoscope.
sts = ps4000aRunBlock(mConfig.device,
mConfig.preTrigSampleCnt, // 2K
mConfig.postTrigSampleCnt, // 6K
mConfig.timeBase, // 39
&mConfig.timeIndisposedMs, // 0
mConfig.segmentIndex, // 1
mConfig.lpReady, // NULL
mConfig.cbParameter); // NULL
// Wait long enough to get fresh data.
usleep(1000000);
// Halt Picoscope to see what Picoscope captured.
sts = ps4000aStop(mConfig.device);
// Retrieve NS and EW magnetic loop and E-field data.
sts = ps4000aGetValues(mConfig.device,
startIndex, // 0
&noOfSamples, // 4 * 8192
1, // down sample ratio N/A
PS4000A_RATIO_MODE_NONE, // ignore down sampling
mConfig.segmentIndex, // 0
&overflow); // N/A

Any explanations as to why the difference in USB 3.0 versus 2.0? Thank you for the help.

Martyn
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Location: St. Neots

Re: USB 2.0 on Picoscope 4424A

Post by Martyn »

The difference between using USB2 and USB3 would be the speed of transfer after the collection has been completed so both should be able to run correctly. The other potential problem would be the powering of the device, and if this is borderline with a USB2 connection.

Can you please contact support@picotech.com to discuss this issue, and share the code you are using so that we can run some tests.
Martyn
Technical Support Manager

phgphd
Newbie
Posts: 0
Joined: Wed Jun 16, 2021 12:33 am

Re: USB 2.0 on Picoscope 4424A

Post by phgphd »

Consider this problem resolved. I am successfully talking via USB 2.0 through my 50 foot USB extension cable. The connection is somewhat problematic in that initially opening the Picoscope is successful only 50% of the time.

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