Author Topic: EEVblog #858 - Red Pitaya  (Read 24960 times)

0 Members and 1 Guest are viewing this topic.

Offline EEVblog

  • Administrator
  • *****
  • Posts: 29943
  • Country: au
    • EEVblog
EEVblog #858 - Red Pitaya
« on: March 08, 2016, 01:14:14 am »
Dave tries to get the Red Pitaya up and running and doing some basic measurements via WiFi & Ethernet.
TLDR:
Many issues: apps freeze, WiFi didn't work, and the apps have only very basic rudimentary functionality. But it's promising, and probably a good solution for those who want to write their own custom (internet enabled or remote) apps or learn FPGA programming, or do custom SDR stuff to 50MHz.
Those that want an out-of-the-box DAQ scope/wavegen/spectrum/network analyser combo tool are better off with the Analog Discovery.

 

Offline Smokey

  • Super Contributor
  • ***
  • Posts: 1592
  • Country: us
Re: EEVblog #858 - Red Pitaya
« Reply #1 on: March 08, 2016, 02:45:39 am »
Why the funny name?  I feel like I'm missing a joke or something?
??
https://en.wikipedia.org/wiki/Pitaya
 

Offline smithnerd

  • Regular Contributor
  • *
  • Posts: 101
  • Country: gb
Re: EEVblog #858 - Red Pitaya
« Reply #2 on: March 08, 2016, 02:49:15 am »
I suspect Dave would have had better luck if he started with a fresh download of the SD card image.
 

Offline Smokey

  • Super Contributor
  • ***
  • Posts: 1592
  • Country: us
Re: EEVblog #858 - Red Pitaya
« Reply #3 on: March 08, 2016, 03:15:18 am »


Wow... Nice "hardware"!
 

Offline EEVblog

  • Administrator
  • *****
  • Posts: 29943
  • Country: au
    • EEVblog
Re: EEVblog #858 - Red Pitaya
« Reply #4 on: March 08, 2016, 03:40:33 am »
I suspect Dave would have had better luck if he started with a fresh download of the SD card image.

Watch the extended version, I looked at that, I had the exact same version as the latest on the website.
 

Offline smithnerd

  • Regular Contributor
  • *
  • Posts: 101
  • Country: gb
Re: EEVblog #858 - Red Pitaya
« Reply #5 on: March 08, 2016, 04:01:39 am »
I suspect Dave would have had better luck if he started with a fresh download of the SD card image.

Watch the extended version, I looked at that, I had the exact same version as the latest on the website.

I will do. Looking at the source code on their website, I see it boots a debian derived Linux image from the SD card, but runs it from a RAM disk, so it doesn't retain any state. That seems like a good idea for a device like this.
 

Offline jamie_1318

  • Newbie
  • Posts: 2
  • Country: ca
Re: EEVblog #858 - Red Pitaya
« Reply #6 on: March 08, 2016, 04:11:00 am »
I bet you had to use the IP address for the wifi in order to browse to the device's website when using wifi. The go button should probably choose the network you actually used to connect it to the web site but I guess they haven't implemented that yet.
 

Offline jeremy

  • Frequent Contributor
  • **
  • Posts: 909
  • Country: au
Re: EEVblog #858 - Red Pitaya
« Reply #7 on: March 08, 2016, 04:24:04 am »
I have used this device extensively, although not in the past year or so. As others have mentioned, it is extremely capable hardware let down by poor documentation and software. However, it is definitely a DAQ/DSP unit and not an oscilloscope (at this stage anyway), and you better learn/know how to write HDLs if you want to do useful things. If you want an oscilloscope, buy an oscilloscope.

Some of this may have changed, but a major problem is that there is no schematic. When I was using it, the uboot port was ancient as well as the linux kernel, and I actually tried to get some patches mainlined for uboot via the xilinx repository so that the device would not have some of these weird bugs that should have been fixed. The patches were accepted, but I couldn't mainline my BSP for the board because the design wasn't open enough (iirc). Also, the ethernet chipset they are using is not supported by mainline uboot, so you have to give up ethernet booting if you want to use the latest version. I believe this is due to some licensing problems. In the end, I had mainline uboot and mainline Linux 3.18 (i think, whatever was the latest at the time) running on it with debian and it was quite a neat platform.

The final issue I had with it is that I couldn't get the data out of it fast enough; I really wish it had a USB3 connection, or that those SATA connectors were actually SATA.

Also the thing gets pretty hot.

Frankly, I suggest that you completely ignore all of the software that comes with, and instead use it as a Zynq dev board with two fast converters, for which it is a splendid device. I only wish it came in Cyclone V form...

As a minor side note, in the video it is mentioned that there is also a 12bit 1MSPS ADC on board, this is actually part of the Zynq and not anything intrinsic to the red pitaya
 

Offline tggzzz

  • Super Contributor
  • ***
  • Posts: 10087
  • Country: gb
    • Having fun doing more, with less
Re: EEVblog #858 - Red Pitaya
« Reply #8 on: March 08, 2016, 08:08:43 am »
Frankly, I suggest that you completely ignore all of the software that comes with, and instead use it as a Zynq dev board with two fast converters, for which it is a splendid device.

I would have used it like that, using the two "external digital" connectors connected to the Zynq. Unfortunately the distribution of GND pins was dreadful: too few even thought some connector pins were unused, all at one end of the connector rather than being interspersed with signals.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Offline station240

  • Supporter
  • ****
  • Posts: 857
  • Country: au
Re: EEVblog #858 - Red Pitaya
« Reply #9 on: March 08, 2016, 08:13:12 am »
Funny I came across this device earlier today when I was searching for something, was planning to look at it.
Guess this answers many of the questions I had, so big thumbs up.  :-+

Lucky the fail button wasn't within reach, would have a flat battery and broken switch by the end of this video.
 

Offline atcurtis

  • Newbie
  • Posts: 3
  • Country: us
    • Making
Re: EEVblog #858 - Red Pitaya
« Reply #10 on: March 08, 2016, 09:02:45 am »
I have found that the Red Pitaya is really sensitive to the wobbles in the power connector so probably when you were lifting up the device, it caused it to reset and reboot. I have been tempted to stick in a big cap.

I didn't like the look of the "pro" apps either so I didn't purchase them. I'm hoping that third-party devs will develop a more useful scope app.
 

Offline G7PSK

  • Super Contributor
  • ***
  • Posts: 3644
  • Country: gb
  • It is hot until proved not.
Re: EEVblog #858 - Red Pitaya
« Reply #11 on: March 08, 2016, 09:30:41 am »
Why the funny name?  I feel like I'm missing a joke or something?
??
https://en.wikipedia.org/wiki/Pitaya

I think it must stand for "Pain in the ass for you all" :-DD
 

Offline Zbig

  • Frequent Contributor
  • **
  • Posts: 856
  • Country: pl
Re: EEVblog #858 - Red Pitaya
« Reply #12 on: March 08, 2016, 10:11:35 am »
Dave, you don't have to right-click and choose "Open in new tab" on webpages; just "mouse-wheel-click" or CTRL-click on a link.
 

Offline Howardlong

  • Super Contributor
  • ***
  • Posts: 4755
  • Country: gb
Re: EEVblog #858 - Red Pitaya
« Reply #13 on: March 08, 2016, 10:56:25 am »
Dave's out of the box experience was roughly like mine, although (a) I used the wired interface and (b) had the USB console running on first boot, so I avoided the WiFi nonsense.

I used a freshly made SD card, and it booted up right away.

My main use is to put it into a bit of one-off OEM gear, and as such I am developing stuff on it rather than using it as an instrument in its own right. However, of course before you start it's good to have a go with the apps. I couldn't get the built in scope app to work at all, it just flatlines. I can see the offset when I zoom in but anything more than that, zip, nada. The built in SA on the other hand worked. What wasn't clear is what you have to pay for and what you don't. I downloaded some of the Bazaar (maybe Bizzare?) apps including the online scope app which did work, but it took some time for me to realise these are different to the built in apps included on the SD card.

It does run very hot, 70C or so. My usual rule of thumb is if it's too hot to touch, it needs some more thermal management.

So, how is it for development? Firstly, the Visual Programming environment just didn't work. I used up my week's trial just trying to open up a non-working link, so I was hardly going to spend good money on a subscription. As Dave suggests, there's little point in the long term becoming depending on a propriatary playground dev environment anyway, but it would be nice to be able to flash an LED at least. It was not to be.

Then I tried to get a demonstration Python script to blink an LED. Surely that can't be so hard? Well for some obscure reason, rather than having a native Python app they decided to do it as a remote blinky using SCPI. I note now that the Python blinky code example has disappeared. Probably wise, it didn't work. But fear not, if you have a Matlab or Scilab they have a remote blinky for that. Please, the point of a blinky is to be simple in terms of deployment and function. The lowest common denominator if you like. Doing a blinky as a distributed application using a ton of irrelevant bloatware is rather self defeating under those terms.

So how about getting a cross-compiling toolchain working? Well, the instructions for a build environment simply don't work. Their Wiki, which you're directed to from their web pages, is for a significantly different and older distribution, one which used software rather than hardware floating point. It wasn't until some hours of investment I realised I'd been largely wasting my time.

To put this into perspective, it took my 25 hours to get a blinky in C built and working. Even then, I had to compile the code on the device itself. I've since got a working cross compiling toolchain working, but you have to use a mixture of out of date recipes and some random button pushing to do so, picking the right bits out of a pot pourri of instructions dotted about the internet. It turns out that you should be using the readme.md in the Red Pitaya github rather than the Wiki for making a toolchain, but the readme.md doesn't tell you how to get an IDE up and working. One other confusion is that when you clone the RedPitaya github using their instructions, not everything is downloaded. I had to download a RedPitaya master zip file and use that to get everything.

I have suggested to RedPitaya that instead of fannying about with pages and pages of recipes to make a toolchain (much of which is just wrong), they distribute a known working VirtualBox VM with a complete working toolchain including IDE for each SD build, plus any additional instructions for optional licensable software like the Xilinx stuff.

To say that my out-of-box experience was dissapointing from a development perspective would be an understatement. You need to be a fairly determined hardcore pointy head to get very far with the Red Pitaya, but it shouldn't have to be that way. One of the key development benefits is that the standard build has a set of pre-baked FPGA configurations suitable for many situations, so in many cases you don't even have to touch the Xilinx tools or hack any HDL. The website is fairly slick, but sadly that's just a veneer, there is a gaping chasm between the fancy website and the hardware especially in terms of development documentation and instrument software. The core is there, it's just not presented at all well for end users, either as instrument consumers or developer creators.

If you want a working USB bench instrument, the Analog Discovery (1 or 2) with the BNC board is without any doubt whatsoever is the way to go. If, on the other had, you have an awful lot of time on your hands, and enjoy tinkering endlessly with Linux, have a great deal of patience, and don't mind an endless game of rabbit holing mostly with dead ends, then you'll love the Red Pitaya.
« Last Edit: March 08, 2016, 11:02:05 am by Howardlong »
 

Online rrinker

  • Super Contributor
  • ***
  • Posts: 1899
  • Country: us
Re: EEVblog #858 - Red Pitaya
« Reply #14 on: March 08, 2016, 01:24:26 pm »
 The one in the "Nice hardware" graphics has a heatsink on the main chip - Dave's does not. Did they stop supplying that, or did Dave get one without by mistake, or is it an optional extra cost item? Or do they figure the aluminum case is sufficient? Still seems too little based on the temps you are seeing. Did anyone else notice the clear acrylic case has openings and mounting holes for a small fan? Can't be trapping that heat and melting the plastic...

 This seems like it could be a really interesting cross domain development platform, but it just isn't quite all the way there yet. A shame, because it does look quite neat in terms of capabilities.

 

Offline D_Dub07

  • Newbie
  • Posts: 1
  • Country: us
Re: EEVblog #858 - Red Pitaya
« Reply #15 on: March 08, 2016, 02:28:49 pm »
Dave, I'm guessing the WiFi didn't work because you had entered the wrong MAC address? The WiFi dongle and built in Ethernet should have different MAC addresses, and in the video you mentioned you entered the same MAC address.
 

Offline signals

  • Contributor
  • Posts: 17
  • Country: us
Re: EEVblog #858 - Red Pitaya
« Reply #16 on: March 08, 2016, 03:01:05 pm »
The one in the "Nice hardware" graphics has a heatsink on the main chip - Dave's does not. Did they stop supplying that, or did Dave get one without by mistake, or is it an optional extra cost item? Or do they figure the aluminum case is sufficient?

I believe Dave said in the video that the aluminum case presses against the chip to act as heatsink. So, the separate heatsink wouldn't be compatible with the aluminum case.
 

Offline RGB255_0_0

  • Frequent Contributor
  • **
  • Posts: 774
  • Country: gb
Re: EEVblog #858 - Red Pitaya
« Reply #17 on: March 08, 2016, 03:39:16 pm »
Micro USB/Micro-B need to die. The sooner everything moves to USB-C the better.
Your toaster just set fire to an African child over TCP.
 

Offline Kilrah

  • Supporter
  • ****
  • Posts: 1758
  • Country: ch
Re: EEVblog #858 - Red Pitaya
« Reply #18 on: March 08, 2016, 03:50:09 pm »
Dave, I'm guessing the WiFi didn't work because you had entered the wrong MAC address? The WiFi dongle and built in Ethernet should have different MAC addresses, and in the video you mentioned you entered the same MAC address.
You probably missed that at some point one could see that the website mentioned that you had to enter the ethernet MAC address in all cases.

Envoyé de mon SM-G920F en utilisant Tapatalk

 

Online rrinker

  • Super Contributor
  • ***
  • Posts: 1899
  • Country: us
Re: EEVblog #858 - Red Pitaya
« Reply #19 on: March 08, 2016, 04:03:53 pm »
The one in the "Nice hardware" graphics has a heatsink on the main chip - Dave's does not. Did they stop supplying that, or did Dave get one without by mistake, or is it an optional extra cost item? Or do they figure the aluminum case is sufficient?

I believe Dave said in the video that the aluminum case presses against the chip to act as heatsink. So, the separate heatsink wouldn't be compatible with the aluminum case.

 AH. I didn't watch the whole thing, after seeing the freezes and some of the other software fails, I sort of stopped paying attention. I didn't notice anything inside the lid that would touch the chip.


 

Offline HwAoRrDk

  • Frequent Contributor
  • **
  • Posts: 632
  • Country: gb
Re: EEVblog #858 - Red Pitaya
« Reply #20 on: March 08, 2016, 05:00:26 pm »
I'm not surprised Dave had problems with the various graphing 'apps'. It boggles my mind that they would even consider doing real-time data visualisation stuff like that on a web-based system. Crazy. :wtf: :-DD

As a web developer myself, I can only begin to imagine the hoops they must be jumping through just to get that kind of thing working at all. Sure, modern web browsers and HTML standards have all sorts of cool features these days, but I doubt any of it was really envisaged to be used like this. Trying to imagine how the graphing works has me thinking that they are probably using a canvas element (or perhaps SVG) for the graph, with a WebSocket channel or two for real-time streaming of the graph data between the browser and a dedicated server daemon running on the Red Pitaya. In that context, a problem like Dave was having with the scope 'locking up', but with the web page controls still being interact-able, could simply be due to the data stream for the graphing being interrupted.
 

Offline blueskull

  • Supporter
  • ****
  • Banned!
  • Posts: 12433
  • Country: cn
  • Power Electronics Guy
Re: EEVblog #858 - Red Pitaya
« Reply #21 on: March 08, 2016, 05:13:37 pm »
The one in the "Nice hardware" graphics has a heatsink on the main chip - Dave's does not. Did they stop supplying that, or did Dave get one without by mistake, or is it an optional extra cost item? Or do they figure the aluminum case is sufficient? Still seems too little based on the temps you are seeing. Did anyone else notice the clear acrylic case has openings and mounting holes for a small fan? Can't be trapping that heat and melting the plastic...

If you watch carefully in full HD, you will notice residual of silicone pad's oil. That means there was a heat sink, be the Al case or a separate piece of heat sink.
 

Offline Fungus

  • Super Contributor
  • ***
  • Posts: 10114
  • Country: 00
Re: EEVblog #858 - Red Pitaya
« Reply #22 on: March 08, 2016, 05:19:05 pm »
I'm not surprised Dave had problems with the various graphing 'apps'. It boggles my mind that they would even consider doing real-time data visualisation stuff like that on a web-based system. Crazy. :wtf: :-DD

My first thought as well.... it's probably a good thing that he never got the WiFi working.

As a web developer myself, I can only begin to imagine the hoops they must be jumping through just to get that kind of thing working at all.

I guess I should be impressed that the waveform display worked as well as it did, but ... the overall insanity of the system won't let me.

So many things could break at any moment. :scared:

« Last Edit: March 08, 2016, 05:23:50 pm by Fungus »
 

Offline Howardlong

  • Super Contributor
  • ***
  • Posts: 4755
  • Country: gb
Re: EEVblog #858 - Red Pitaya
« Reply #23 on: March 08, 2016, 05:27:58 pm »
I'm not a web developer (by choice!) but I thought HTML 5 was designed to allow all this kind of thing, replacing Flash for example.
 

Offline zaoka

  • Frequent Contributor
  • **
  • Posts: 374
  • Country: us
Re: EEVblog #858 - Red Pitaya
« Reply #24 on: March 08, 2016, 06:53:27 pm »
Dave,

You promissed to do "features" video of a new Agilent meter as well as teardown of another model that you have.

Please compare to Fluke 87V, how fast it settle, how fast it autoranges etc.. :)

Thanks and great video!
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf