krb686

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  1. Hey, thanks. Yeah I can try a different padding character, but I was under the impression FF was the best because even if the receiver is out of sync, it will still sync since it will think the FF byte is just IDLE state. By the way, that reasoning of using an FF byte for padding opposed to an AA byte is addressed specifically in the 2nd answer by "MikeJ-UK" to a question on serial UART, on stackexchange. The baud rate is a little weird, it's 781,250. That's because I'm dividing down from the 100MHz clock on the Nexys 3. I have a PMOD running at 195 kHz that essentially outputs new samp
  2. Using the analog discovery with waveforms 3, it seems like the UART interpreter is telling me things that are incorrect. I could be completely wrong, and maybe I don't know enough about UART framing to tell, but if that's the case let me know, The data stream I am sending is arranged like so: [FF pad byte] - [data(lower 6 + 2 tag bits)] - [FF pad byte] - [data(upper 6 + 2 tag bits)] - [FF pad byte] - [checksum] To get a much better look at the bits, go to: http://s306.photobucket.com/user/Krb686/media/waveforms_uart_bug.png.html?o=0. Then hover over the image at my photobucket, and click t
  3. Thanks for the help, hamster. I got this to work surprisingly, and I am successfully reading in some data to a python script. It works similar to the script you sent me. While I was getting this working, I encountered something interesting on my Analog Discovery that I'm making a separate post about, and I'll link to it from here.
  4. I've got the Nexys 3 board and it's reading some data from a peripheral, but I can't debug what's on the board because I'm not about to spend 600+ on chipscope. So I've thought about the possibility of using the UART to send data back to the PC to analyze there, but the problem is there's really just about zilch information out there on how to use the UART on this board. Let's be honest, the Digilent Nexys 3 user guide (pg 12) is absolutely useless in this regard. It explains what the UART does from a high level, and mentions using free FTDI drivers, but has absolutely no information whats
  5. I recently purchased the PmodMIC to use with my Nexys 3 board and Analog Discovery. Finally after a bit of coding, I seem to have gotten it to run continuously, but I have just a few questions. In the PmodMIC reference component PDF, it states: The VHDL component is an entity named PmodMicRefComp which has five inputs and five outputs.The input ports are a 50MHz clock,.... (BTW, I think the 5 inputs, 5 outputs thing is a typo ). But my first question is: 1) Is it possible to lower the sampling rate? Apparently the 50 MHz input clock gets divided down to 12.5 MHz inside the PmodMICRef
  6. Very cool! Thanks for the answers. WF3 definitely looks like a step forward from WF2, that's for sure. Though how does the device manage to stream to 1 million samples when it can only handle 16K internally? Does it attempt to transfer to the PC while more samples are being taken? If you folks at digilent are ever thinking about redesigning the Analog Discovery for a 2.0 edition, I would certainly be willing to pay more money for either 1) a larger internal memory to store more than 16K, or 2) the ability to truly stream the samples to PC (USB 3.0?), and thus only be limited by the amount
  7. I think you make a good case. Fortunately for me, I am a student and got the student pricing on the Analog Discovery, but before I purchased it, I was also looking for a fairly cheap option ($100 - $150 range), and came across the Saleae selection. If it were not for the faster sample rate of the Discovery over their equivalent $100ish choice, I might have picked the Saleae. But I think you are right, I think there is a demand out there for a cheaper analyzer with limited functonality.
  8. Thanks, that clears up a lot. If you don't mind, I have a few other questions if you can answer them. What is the difference between the two versions you have linked in your PM? Is the version 3 just a beta? Patch notes or change log anywhere? Also, another quick question regarding a specification of the Analog Discovery. The specs state it is capable of 16K transitions per pin. So this is an internal buffer limitation on the device? Yet I am not limited to just a single buffer, and can specify many buffers to be filled in WaveForms. Is there a limit to how many buffers I can specify? A
  9. I just bought this product recently. It looks pretty nice, and I'm pretty sure I'm not using it to its full potential. The specs say it samples at 100MS/s, yet that certainly is not happening with mine. From the looks of it, I see 2048 samples at 4.005 kHz. And by counting the marks between the time divisions (1ms apart), it does look like approx 4kHz. Why is this not running faster? This is a far cry short of 100MS/s. I also see no setting anywhere to change the sampling rate/speed.