Oscilloscope “DSO Nano”

Some two months ago i bought  a digital oscilloscope “DSO Nano 201″ on generic cialis in stock eBay, i was so thrilled when i got it, and it keeps me (and my friends) surprising on and on, even after few moths of using it so i decided to share my experiences with you.

Nano DSO oscilloscope is an open source project that was developed by “e-Design Co., Ltd…” I think it is a Chinese company, but i’m not sure, the device is manufactured in China. If you decide to apcalis generic viagra purchase one, price is around 70 dollars with postage, the price will probably drop even more since they launched the new four channel version that runs up to 30MHz, and sells for about $ 200.

According to the Internet you can find similar open source projects based on AVR and similar controllers with monochrome graphic display, however this project for several reasons in the first place:
1) Measurement display at 320×240 pixels which is the same as most tektronix’s TDS Series oscilloscope’s whose display is 5.8 inches, of course, performance is incomparable (in favor of Tektronix, of course),
2) Mobility is another important issue, because the dimensions of approx. 4 x 2 inches fit into almost any pocket, cialis soft tab videos sometimes I fear that it might broke, because you literally forget that in your pocket,
3) Power supply from its own internal battery that is charged via USB, ther open source projects require some external power source.
4) Save the measurement settings (time-base, Voltage divisions, trigger …..) and screenshots (in BMP format) on the microSD card is a very handy feature that is except for the afterward analysis of the measurements can be used for writing documentation to paypal generic cialis show some kind of wave with or without measurement.

The device is not perfect as it may seems, there are a few details that i do not like:
1) Crosstalk between signal generator that can be seen in a large gain, or less V / div.
2) The relatively small sample rate of 1Msps that good enough for me, because i use it for sound measurements, but higher sample rate would be better.
3) The factory firmware is almost  unusable, there are millions of small bugs, for example when changing the time base some pixels always “stuck”  on the display and stuff like that, if you get a device install any other firmware, eg Benf 3.4 or PAULs 1.5. I use my own version compiled from several existing distribution, there are still some bugs with the RMS and the decibel calculation as can be seen in the photo below, but i don’t have time to fix it currrently…  :)

A few words about the hardware: the model 201 runs on the ST’s ARM Cortex-M3 32-bit microcontroller with 128kB of flash memory and 20KB RAM. Microprocessor clock speed is viagra best price sildenafil 72MHz, which ks generated by internal PLL oscillator. As you can see on the schematic system is a very simple, device has a USB port that can operate only as a “slave” so it can not be programmed to viagra pfizer india communicate directly with the memory stick, but can work as a memory stick it self, which is used in some versions of firmware, in my version too. USB is also used to update the firmware, there’s more information below. The device has a charger for lithium-ion batteries, generic viagra 25mg which charges the internal battery while the device is turned off and runs on USB power supply while turned on. As seen from the photographs, measurements are displayed on viagra vs cialis licensed pharmacies online the 2.8 inch color graphical display, in 65 thousand colors:), a resolution of 320 x 240 pixels, which is more than enough for the display area of diagonal 2.8 inches. On the outside, it has a USB port, connector for the probe, microSD memory card and cheap viagra credit test signal pin.

In the schematic you can see the internal JTAG port for the first device programming, used in factory to program USB bootloader in flash memory. In addition, you can see the SP3232 level converter (3232 is a 3 volt version) RS232 communication, which is here used as a power source (+5 V and-5V) for the analog section, 6 buttons, two power regulators (xc6 ….), the two operational amplifiers in the upper right corner, and input attenuator with the 4051 CMOS logic chip. Very simple design, cheap cialis tadalafil 20 mg yet so usefull!

The input signal is sampled @ 1Msps, at least so says the manufacturer, but in practice this is less because the data sheet specifies the sampling rate of about 850kHz @ internal bus clock speed of 18MHz, which is quite enough. Especially if you need for audio signals, and for many other (slightly) faster signals. Resolution of AD converter is 12bit.

As I mentioned in upper text; you can see crosstalk “problem” on the screenshot, due to poorly designed press, one of simplest solutions to this problem is a software generator turn-off when not needed, i’ll add this option in my next firmware version release. I think I mentioned somewhere in text that the generator frequency can be changed from 10Hz to 1MHz. This screenshot is taken directly on the oscilloscope, as file in BMP format and copied via USB to computer, and uploaded to the website, without any graphical editing intervention.

Here you can see a screenshot during debugging firmware, i accidentally shot it while analyzed some of the functions that do the measurements. You may have noticed in the bottom-right of column has a”FT” submenu option that other firmware versions do not have.  It’s FFT option that do not work since i run out of RAM; there are few buffers for measurements and calculations, and this controller don’t have too much of it. The algorithm that I used the so-called in-place FFT, which uses the same buffer for the measurement and the result (real part). Perhaps it would be nice to mention that ST has some kind of library that includes DSP FFT, PID control, and some filters do not remember exactly this by heart, in any case it is good to know what you have at your disposal if you need it sometimes.

If for example, Tektronix decided to make a similar device that would look something like this:

Note: This image has nothing to do with the company TEKTRONIX INC. nor with any products of that company, this is just an attempt of witty author of this article to show his own vision of eventual future. :)

Firmware are updated via USB and DFU bootloader (DfuSe Demo) applications that can be downloaded from ST’s website. Procedure for the following: Install the package DFU application fromh ST’s site, connect the DSO nano with a USB cable to your computer, press the “-” and turn on the device, now that it should come up e-design logo, Windows will ask for drivers, You can find them in the folder where you installed the ST’s programs.

When compiled the hex file (do not forget to set the offset, how; it depends on the compiler), with the DFU-manager convert hex into dfu file (set the target of a 00 -> internal flash), load the file into dfu “DfuSe Demo “application, click the” upgrade “and after a few seconds, that’s it! Turn off the device and that’s it. If you then display appears white, perhaps you forgot to load both the DFU file. To avoid 32KB limit of the evaulation versions of the compilers, the developers have thought of a firmware divided into two parts: LIB and APP, in the LIB they placed in the initialization function, interrupt handlers, and some low-level drivers, and  in the APP part of the firmware they put oscilloscope application (one that you can see on the display), file system driver, USB memory device driver.

If you are working with the GCC compiler, then you have no problem with the license, soyou can fit all into one hex file. If you would like to have everything in one file dfu-in, such as myself, then you can use a neat trick. Open APP hex in a text editor, copy everything except the last line (depending on variant and hex file) and insert the copied content before the last line in the LIB hex file (so that “: 000001FF” or something like that ends up as a last line), and now you have everything in one hex file! Next you know the procedure, the DFU conversion… …

If you are interested in more information or have any questions about anything, feel free contact us. This article will probably be updated in the future, so check up on us every now and then … .. And finally here is the link with all documentation and source code.

 

 

Schematic & Firmware: Dso Nano Google Code

Wersi

Impressionable and talentless idiot on a mission to entertain

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  4. John Travolta says:

    hi,
    i bought one of this too. i have never used oscilloscope in my life.
    i was hoping to use it with my electronics after i bought it.
    but so far i have figure out how to i use it.
    if you can help me with it.
    1. how to measure voltage.
    2. how to measure frequency
    3. and see wave form.

    i have a digital signal generator. which can generate sine wave, square wave and triangular wave, it can generate from .01 hz to 1MHz. it have an lcd display to show the output. but i wanna see it on my oscilloscope.

    i have gone through the manual that it came with. but still don’t understand a thing.

    HELP PLEASE.
    thanks a bunch