Some of you may have read the post on the attempts at a 2 Ms/s version and how it turned out to conflict with real-time trigger search. Giving up on the true real-time trigger is not really an option, but this version still offers a no compromise increase in sampling speed from 857 ks/s to 1 Ms/s.
RAM is a limiting factor when developing for embedded devices, but there is no reason we shouldn’t use it all. In this update, sampling depth has been increased from 3072 to 4098 points.
V2 hardware has two hard-wired interconnected GPIO’s intended for interleaved sampling. Firmware however was never updated to reflect this modification and so a pull-up (40k-ish to 3V) is incorrectly present on the input to the analog digital converter. This update will detect if the two GPIO’s are connected and disable the pull-up to avoid this conflict. V2 users are advised to recheck their calibration after upgrading due to this change.
Battery level has been adjusted so that the empty level (red hollow icon) coincides with the drop out voltage of the regulator. Operation should be ok until this stage, but you’re advised to switch off your Nano whenever you see the red icon as measurements can no longer be trusted.
In this industry (IT that is), today is always the better day to have new solutions ready. If we wait for the next version, we’ll end up doing just that – wait!
I need help. I can not save waveforms, screen capture bitmaps and snapshots on micro-SD cards. Can I get a copy of the correct directory structure and files for a micro-SD? I’m using a 2GB micro-SD FAT16, DSO Nano V1, DSO firmware version 3.4. Thanks.
Hello benf
Is this possible:
Rather than save a buffer on an SD card could not be
send these buffers via USB to a PC and as a measure of capture (almost real time).
we would have a mode captures burst '. The shipment would be via USB
faster than recording on the SD card.
Double thank you for your response and your excellent software (I use it almost every day)
I am quite impressed with your latency of selected measurement item from the pop-up. Excellent job with the FIT trigger option. It serves the new users as well as experienced users.
The Nano is very useful at this time and those functions I referenced above may have been in previous releases but I just looked close enough to find them today. I am closely examining the functionality for more lesson tutorials.
One request would be to allow an option for the trigger sensitivity lines to remain displayed while the trigger level is adjusted. Maybe a sticky on/off option for display of the trigger sensitivity cursors.
One point of clarification on the COUNTS measurement item. I understand it is transitions but I don’t understand the duration measurement. Is this the counts within the entire buffer as I suspect?
When I set the buffer pri to POST and then use long “M” to set the trigger to zero offset; I can then scroll right arrow about 98us with a timebase of 2us/Div. What is this displayed empty space?
Is it empty buffer memory, or is it related to something else like acquisition setup time?
This is possible, but you would then need PC software to process the data stream. Some speed constraints to consider are as follows:
USB on the Nano conforms to USB 2.0 full-speed (12 Mbit/s). SD write speed is roughly the same. Sustained end-to-end speed for either interface (USB or SD) however is likely to be significantly less. Maximum sampling rate on the Nano is currently (V3.40) 16 Mbit/s.
The functionality of the signal generator is the same as for V3.3x which was confirmed to work also for V2 hardware. Hardware version is displayed on the startup screen (V1 or V2) so you can verify that your Nano is identified correctly.
Personally I think the double lines obscure the displayed waveform and so prefer the single level line (sensitivity is more of a set-and-forget value). This of-course is a subjective preference and so an option to choose may be the way to go.
The PULS measurement is a count of low-to-high (below/above trigger) transitions across the full capture buffer.
Any single capture will use the full buffer capacity (currently 4098 points) with the trigger position shifting left/right within 1/3 of the buffer between individual samples. In order to keep the trigger centered on screen and still allow every single point to be viewed there will be empty space (no data) far left and/or far right on the display. This empty area is outside of the buffer and size is related to trigger position.
i ask you because you know the very detail of software… is it feasible to keep sampled signal in 8 bit (a virtual screen)?. This way transfer requirements (for both card and USB) will be kept to a minimum (8 Mbit/s).
Note: as far as i know ADCs are 12 bit (12 Mbit/s), aren’t they?
When doing DMA sampling from ADC, data is obtained from 16-bit registers although with only 12 significant bits per sample. This is where the 16 Mbit/s is coming from.
We need the full 12-bits to maintain a reasonable dynamic range across all scales, but I’m sure post-processed data at 8-bits would be quite acceptable (the Nano waveform grid is only 200 points vertically).
I had some quiet time to scan the forum for ideas and suggestions again and thanks to all for the excellent feedback.
Also I’d like to excuse my sometimes terse comments. Please don’t confuse this with lack of respect in any way and don’t hesitate to challenge or correct me. I’m way past my teens and not after boosting my own ego in any way so bring it on (be prepared to get challenged back however).
There are some very knowledgeable people here such as Slimfish and Shazam who knows the Nano hardware better than any of us. They have both contributed to a long thread on considerations for the V2 design modifications that may interest you. Also if you haven’t looked at the video tutorials posted by lygra, please do so, they are a delight.
Yes, thanks to Slimfish and Shazam from me too I followed their threads closely because of their commitment to enhance the nano. I’m not much into the hardware of the nano but I’m curious to know if any of their great ideas did make it into the V2 (or quad)?
For those looking for an SD card that works, I just purchased the $10 2GB SanDisk SD card at Walmart and it works fine. I was reluctant to purchase because I didn’t know if it would work; but it does!
