Larry McGovern Posted November 12, 2016 Report Share Posted November 12, 2016 I'm seeing some strange behavior with the Papilio One Logic Analyzer any time I select a sample size greater than 6 kB. It is easiest to demonstrate with an example. I have a test signal coming in on Pin 0. I am writing the sentence "The quick brown fox jumped over the lazy dog" over a serial port at 115200 baud, and repeating the sentence every 30 msec. The sentence itself takes 4 msec to write. The first image below shows a 1 MHz, 6 kB capture enabling channel group 0. This should cover 6 msec of data, and that is what I see on the logic analyzer. The UART analyzer shows the correct sentence coming across. The second image shows a 50 kHz capture, with 120 msec of data. This shows the sentence is repeated every 30 msec. The third image shows a 2 MHz, 12 kB capture enabling channel group 0. It should look exactly the same as the first image, but it doesn't. Instead, it shows a 1.5 msec word, 1.5 msec gap, and another 1.5 msec word. The two words read "er the lazy dog er the lazy dog". The fourth image shows a 5 MHz, 24 kB capture. Again, it should look like image 1 but it doesn't. Instead, we see the last 0.75 msec of the sentence, repeated 4 times. It essentially says "** dog" four times, where ** are garbage characters. That was all with only channel group 1 enabled. When I enable all four channel groups, and do a 1 MHz, 6 kB capture, I am told I will only receive 1.5 msec of data, but instead I receive 6 msec of data! When I try to capture 12 kB or 24 kB of data, it complains "Sample count too large for chosen channel groups!" So... Is this a known bug, or something new? I installed the bitfile using the "OLS" button on DesignLab 1.0.7. I have been extra careful to ensure I have selected the Papilio One 250K on both DesignLab and OLS. I've even uninstalled and reinstalled DesignLab. I also have a Papilio Duo, and the logic analyzer works for me with that board. Any ideas? Anything I should try? Quote Link to comment Share on other sites More sharing options...
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.