JColvin
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Posts posted by JColvin
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Hi @rain,
I have split your post off into a new topic.
You could just use some sort of external module, be it a Pmod SWT or something else, as a replacement option for the collection of on-board switches, but there are a few catches with this method.
One is that you will inevitably lose out on total available pins that are available to the user. This might not always be an issue if a design doesn't use all of the general purpose input/output pins, but it feels like kicking the problem further down the road.
The second is .xdc file (file that tells the Xilinx software which ports in a design are connected to what physical pin on the FPGA) that Digilent provides will no longer be correct. While you can certainly edit the .xdc file to instead say that all (or just a select few) of the switches are instead attached to some other FPGA pin that goes to a Pmod port (and sets up a good habit of checking and becoming familiar with the .xdc file), this can become a hassle to have to correct every time, especially if the external switches move to different Pmod ports and it is a different collection of switches on the Nexys that are being exchanged out.
It's been a few years since I've had to do any soldering and I wasn't an expert by any stretch of the imagination, so take this next bit with a grain of salt:
I do not know which Nexys board you are using (Nexys A7, Nexys Video, etc.) nor do I know your set up or if you are just replacing the slide switches for different ones or with entirely different I/O devices or whatever, but I would probably look to get some sort of clamp stand (maybe even one designed to hold up an iPad rather than just alligator clips) to hold the board up on its side so that I could heat the underside of the through hole contacts with a soldering iron and pull out the switches with some sort of needle nose pliers.Let me know if you have any questions.
Thanks,
JColvin -
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Hi @rpatel,
For the SMT4, I have been informed that the worst case for Vdd is 115 mA and the typical usage is 90 mA with JTAG running at max speed and UART running at 1 MBaud. The Vref current at 30 MHz is 12.5 mA typical and 35 mA max (unless you short the outputs, then Vref would probably peak out around 170 mA).
You didn't ask about minimums, but when the USB controller is held in reset, the current consumption is ~20 mA. When it comes out of reset and enumerates on the bus it's ~87.5 mA.
Let me know if you have any questions.
Thanks,
JColvin -
Hi @Kevin.C,
3.22.19 is an "official" beta build (https://forum.digilent.com/topic/8908-waveforms-beta-download/) as opposed to a formal release (though the difference between a beta build and a formal release mostly boils down to the amount of documentation involved along extra hunting for bugs).
I do not anticipate a formal release version to be made for at least a couple of months; it depends when a new Digilent Test and Measurement device comes out, but I have not seen any announcements as of yet.
I will make a note to ping you once a release version has been made.
Let me know if you have any questions.
Thanks,
JColvin -
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Hi @VictorV,
I wanted to let you know that we have reproduced this issue and have reached out internally to get some additional information about this.
Thanks,
JColvin -
Glad it worked.
I recall that I also had to use a fair amount of force the first couple of times for my Analog Discovery 3 device, but it stopped being an issue after about 5 or so cycles.
For what it's worth, after about a year of use and constant switching between different MTE cable sets and adapters (i.e. regular use for a support day job), I have no concerns about the cable coming loose, even on "intentional accident".
Thanks,
JColvin -
Hi @yassine,
It doesn't look like you've pushed the cable in far enough. The whole section with divots should be covered by the device, so that the (poorly drawn) red line is flush with the front face of the AD3.
You'll end up bumping into the plastic that I mentioned once it goes in all the way. This photo of the AD2 shows the main idea of what I've trying to explain by the shield/flashing and how far back it is compared to the front face of the device (the 2x15 connector used in the Analog Discovery 2 is identical to the one used in the Analog Discovery 3).
Let me know if you have any questions.
Thanks,
JColvin -
Hi @gibby,
I'm not certain what radiated emissions you have in mind, but the MTE flywires themselves can act a bit like antennas but you'll then run into bandwidth limitations (depending of course what frequency range you're looking for). Using the BNC Adapter (or a device built with BNCs and high bandwidth, https://digilent.com/reference/test-and-measurement/analog-discovery-pro-5250/fm-radio) might end up getting you some better results.
You may find this Forum thread from a number of years back of interest:
Let me know if you have any questions or if I'm completely misunderstanding your question.
Thanks,
JColvin -
You will need to ensure that the flywire assembly is fully inserted into the device; there is plastic "shielding/flashing" that the assembly should be pushed against (there is no concern about breaking the pins or something like that).
I have attached a couple of photos to comparatively show how far the assembly should be connected. Basically, only half a centimeter of the housing should still be visible.
Please let me know if you are still encountering issues.
Thanks,
JColvinP.S. my AD3 is a prototype which is why the outer shell will likely look different than yours
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Hi @decal,
The breadboard breakout (the one with the 2x15 DIP style pin set) can slot into any solderless breadboard. You'll of course then need to use a variety of jumper wires to connect the numbered row to the rest of your circuitry, much like it shows for the in-use photo on the Breadboard Breakout Resource Center.
As for the Breadboard Adapter, the Large Solderless Breadboard will not physically sit on top of it. You could, of course, use jumper wires from the 2x15 female header to the large breadboard, much like you would do for the included half-size breadboard that does fit on top. As always, there is no electrical contact between solderless breadboards and the PCB because the solderless breadboards are, well, solderless.
I couldn't find my Breadboard Breakout adapter or the formal Large Solderless Breadboard, but I've attached a picture showing the size discrepancy between the Breadboard Adapter, the half-size breadboard, and one of the Canvas's for the Analog Discovery Studio (which is a similar size to the Large Solderless Breadboard).
Let me know if you have any questions.
Thanks,
JColvin -
Hi @Duh,
You should be able drag each of the signal groups via the small rectangle on the left hand side next to each group. It's not particularly visible when compared to moving a browser tab but it should work:
I don't think you can readily change the order of things within a bus though (such as the chip select and clock within SPI), at least as far as I can tell. Maybe the WaveForms developer (not me) will consider that option for a future update.
Let me know if you have any questions.
Thanks,
JColvin -
Hi @Clyde,
The Analog Discovery 3 has 9 MHz bandwidth unless you're using the BNC Adapter which bumps the bandwidth up to 30 MHz: https://digilent.com/reference/test-and-measurement/analog-discovery-3/specifications#analog_input_channels, though the ADP3250/ADP3450 both have the 55 MHz analog input bandwidth like you indicated (ADP2230 has 50 MHz bandwidth for its two analog input channels).
Regarding a SPI bus transaction on the AD3 specifically, I would probably be using the Logic Analyzer instrument on the digital channels and have a result more like the splash screenshot I took for AD3 reference manual: https://digilent.com/reference/test-and-measurement/analog-discovery-3/reference-manual#logic_analyzer.
If you're instead looking for a more traditional MSO setup, you could use the Digital view inside the Scope instrument to view both the digital and analog input channels in a time correlated fashion (rather than having the logic analyzer and oscilloscope run simultaneously in two separate windows) along with the option to interpret one of the analog input signals as part of the digital bus directly, much like I've done here with the Scope Channel 1 being subbed in for the SPI peripheral out controller in line (MISO):
The catch with style is that the analog to digital interpretation is done in WaveForms, so you won't have the option to do any digital protocol triggering on a bus utilizing an analog input. If they are separated out, like how MISO is, you can still trigger off of the digital protocol values, like how I did above to trigger on the h40 value for MOSI.
If you're looking to analyze digital protocols directly within WaveForms though, I personally think you'll have an easier time with either the ADP3250/3450 or the ADP2230 since they both have on-board DDR memory. That'll let you get much longer captures relative to the Analog Discovery 3 which are more helpful for digital protocols where there can be a comparatively long amount of downtime between the fast bursts of communication.
The point is moot of course if you're only ever looking at a few frames at a time.Let me know if you have any questions.
Thanks,
JColvinP.S. The Analog Discovery Pro 5250 (a rebranded version of the NI VirtualBench 8012, now sold by Digilent) also has 100 MHz bandwidth for it's two analog input channels, but it lacks DDR memory and has a different price point than something like the Analog Discovery 3.
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Hi @Evan Cleary,
My understand is that it is possible to do, but you need to change out a couple of DLLs to make it work as per this specific post (and the one chronologically after it):
Let me know how it goes.
Thanks,
JColvin -
Hi @Clyde,
I don't know what your specific needs are, but other devices, such as the Analog Discovery 3 or the Analog Discovery Pro 2230, have eFuses to limit the total power output (which you can set the value of) on their adjustable -0.5 V to -5 V and +0.5 V to +5 V supplies.
Thanks,
JColvin -
Hi @Dominic,
Are you using the Digilent Toolbox rather than the old Data Acquistion toolbox which did not support non-blocking functions? There's a guide on how to set that up here if this is the case: https://digilent.com/reference/test-and-measurement/guides/matlab-getting-started.
Please let me know if you are using the new toolbox but still running into this issue.
Thanks,
JColvin -
Hi @BlazeIt,
I suspect this may more likely be the source of a different issue (driver, baud rate, etc), but I have sent you a PM.
Thanks,
JColvin -
Hi @Clyde,
I have moved your question to a more appropriate section of the Forum where the engineer most familiar with the Analog Discovery Pro 3450 will be able to give accurate insight into this.
I know that the trigger DIO signals themselves are protected by ESD diodes and PTC thermistors, but I am uncertain about digital supplies themselves regarding overcurrent protection.
Thanks,
JColvin -
Hi @BEBERL,
If the transducer is analog based, i.e. sends out some sort of voltage based on the measured pressure, it might be possible to interface the Analog Discovery device (whether AD2 or the newer AD3) with it. I'm guessing it is analog based on the picture that shows 3 wires (presumably power, ground, and the signal) going into the extension cable.
If it instead uses some sort of serialized digital interface, you would then have to figure out the communication scheme that it uses, which could be quite a bit of debugging to figure out as I'm not readily seeing any documentation for it. If this is the case, the Analog Discovery device could still potentially interface with the transducer, but the level of effort to get it working, if at all, is a big unknown.
If it is an analog output signal, you would need some sort of physical adapter to readily connect to the wires (or be willing planning on splicing the cable open to connect to the individual wires via a breadboard or soldering pin headers to them).
You could then use the analog input channels on the Analog Discovery device to measure the variable voltage coming out of the transducer as well as some sort of math channel to convert the measured voltage to the correct units. I'm presuming there is some sort of documentation out there that would tell you what first or second order linear equation the transducer follows.As for powering the transducer, the Analog Discovery device can probably do that for you as well with its external power supplies. The catch with this is that I don't know what voltage the transducer operates at.
If you have some sort of datasheet regarding the electrical specifications of the transducer as well as the wiring setup, I might be able to provide a more conclusive answer for you.
Thanks,
JColvin -
I am also copying @malexander for visibility on the Adept side of things.
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Hi @jenga,
The record mode (I'm presuming that is what you are meaning by streaming) bottleneck for the ADP3450 is limited by the connection to the host computer; either the USB 2.0 connection or the Ethernet connection, depending on which configuration you chose.
As both communication options are packet based, data is transferred in chunks. Because of the on-board DDR memory, the streaming of data in chunks is largely mitigated since the device can continue to capture data and store it in the DDR memory while some subset is transferred over to the computer (presuming you aren't attempting to capture data faster than you can transfer it over anyways). The WaveForms Help tab has typical values for transfer rates and latency:
In terms of other numbers, each analog input is stored in a 16-bit (2 byte) format, as well as the 16 digital channels being represented in a 2-byte format, so you'll correspondingly be limited in what maximum sample rate you can achieve based on how many channels you have enabled.
There are several built-in Record mode examples in Python that should be of help:
USB 2.0 with its overhead tends to top out at around 40 MByte/s, so with 3 two-byte channels acquiring data over USB, this ends up capping you at a sampling rate a bit over 6.5 MHz (best that I can tell, the screenshot from record to file is showing 13.1 MS/s // 26.2 MB/s for the measured rates because it is not taking into account the remaining third of the 6 bytes per sample bandwidth portion that the digital data is taking up):
With a gigabit Ethernet connection, you'll of course then be able to achieve the faster rates:
If you are wanting to have faster streaming, I would instead point you towards the ADP2230 with its USB 3.2 Gen 1 connection:
Let me know if you have any questions.
Thanks,
JColvin -
Hi @Kevin.C,
I am uncertain on the public key for WaveForms; that will be answered by the WaveForms developer (Attila) on the https://forum.digilent.com/topic/28525-digilent-adept-runtime-package-header-is-not-signed/. I saw you pinged him on it yesterday and that he got another ping from the Adept developer today, so I hope to hear some details on this once his European timezone is in normal business hours to confirm if the key is different than the Adept key and if the 3.22.2 release will be back-updated.
The public GPG for Adept (you need to get Adept Runtime installed first on Linux prior to WaveForms) can be found here: https://cloud.digilent.com/myproducts/Adept?tab=2.
Let me know if you have any questions.
Thanks,
JColvin -
Hi @Ayesha Zaman,
It is the buffer size of the Analog Discovery analog input/scope (as that is what you are using) that needs to be kept under the value.
For example, if you are wanting to acquire 10 us at 100 MS/s, that would be 1000 samples (1*10^-5 x 1*10^8). Correspondingly, the maximum amount of time for a single acquisition at 100 MHz for the AD2's 8192 sample buffer size would be 81.92 us.
If you wanted to acquire data for a longer period of time, then the sample rate has to decrease to 50 MHz (or lower, depending on the length of time) for the 8192 sample buffer to be "spread out" enough to encompass the full desired time frame.Thanks,
JColvin -
Hi @jcanion,
The Network Analyzer instrument has a Bode plot as its default view. The Help tab has built-in documentation on all of the different settings:
There is also a tutorial version on using the Network Analyzer on the Digilent Reference site here: https://digilent.com/reference/test-and-measurement/guides/waveforms-network-analyzer, which is also listed on the Analog Discovery 3 Resource Center here: https://digilent.com/reference/test-and-measurement/analog-discovery-3/start#tutorials.
Let me know if you have any questions.
Thanks,
JColvin
Would using a USB Hub for UART communication cause any issues?
in FPGA
Posted
Hi @digility,
A hub will only become a problem if the USB traffic back to the host computer (whether that's UART or JTAG or your keyboard/mouse or whatever) becomes congested and you end up losing samples (or if your hub cannot provide sufficient power to all of the connected devices).
A lot of computer motherboards have internal USB hubs for their multiple USB ports (albeit potentially with controllers for each connection depending on the setup). I have two USB hubs (out of necessity) for the collection of Digilent devices that I have at my work station.
If I know that I am going to be streaming a lot of data at a rate that can't afford to have dropped packets (or that is going to saturate the bandwidth of the hubs connection back to the host computer), I'll just make sure that I let that device have a direct connection to the host computer so it is not competing with other devices for bandwidth.
But using a device with a USB 2.0 connection, a keyboard, and a mouse on some hub should realistically not be a problem, as keyboards and mice are pretty "light weight".
I don't quite understand your use case of communicating with the FPGA over UART while also configuring the FPGA as that would reset the entire FPGA (unless you're doing partial reconfiguration that doesn't touch the UART portion?)
Thanks,
JColvin