Can confirm the noise, even with the Logic analyzer completely disconnected
By completely disconnected you mean the minimum required for the Scope to detected and activate the logic analyzer, correct? The microcontroller that was added for the LEDs, is it active when you detect the noise?
100% certain on D11 and D14? they break the pattern of all the others
Does the Channel - Channel skew line up with your trace lengths, if not we may be able to forward correct for it on a new PCB version.
Today I noticed the LA can be activated without the digital probe connected (I don't have one). What is the purpose of the probe detect on pin 1?
I don't have any noise in the digital channels when the LA is active and there is no probe connected to the scope
Any thought on using mini displayport for cables? They have orientation and same lanes as hdmi.
Cables are pretty cheap. https://smile.amazon.com/Cable-Matters-Mini-DisplayPort-Black/dp/B0777RKTJB/ref=sr_1_8
But I didnt check on the connector prices. I suspect the usb-c are much cheaper...
Wow, I am so glad that I just made this account! Would you be willing to share design files and firmware so I can make a run of PCBs?
Thank you kindly,
jMachina
Revision 2 PCB is here: https://gitlab.com/thmjpr/stm32f03_la_monitor/tree/master/PCB_Rev2
- See readme.md
- A 50 pin connector available from LCSC but has no polarized part in the middle, so could accidentally be plugged in upside down. One polarized version is: SFH11-PBPC-D25-ST-BK (digikey)
- CC1/2 resistor values might need to be played with or voltage measured, can't recall if I used what was on the schematic.
Attached some parts I bought from LCSC but its not the complete BOM, just use for sourcing ideas.
I'm a little uncertain reading through this thread - does the logic analyzer you guys designed improve anything off the Rigol design, or is it simply a matter of reducing the $400 price tag off the Rigol product to BOM plus hobby time?
This is fantastic, if you have any spare boards / parts you'd like to sell I'm interested.
BTW there is a SCPI command for LA time offset, :LA:TCALibrate 0.0000002 +/- 200ns but its not working (read back is always 0), suspect in another thread that its not actually been implemented yet.
Hello thmjpr,
Is Rev2 like a "perfect" version so far?
Really love your USB-C idea. I'm thinking to make one and guess it can bring some fun time with my new MSO5072.
BTW there is a SCPI command for LA time offset, :LA:TCALibrate 0.0000002 +/- 200ns but its not working (read back is always 0), suspect in another thread that its not actually been implemented yet.First of all, congratulations for your work!
Now, my small contribution:
Those SCPI commands are implemented in the FW. I've checked them in the latest FW. (and there are plenty of other functions that are not currently exposed to users, but equally implemented)
Don't know if you are aware of all the MSO5000 SCPI commands that are currently externally exposed?but maybe you have to manually enable "calibration mode". Try these commands:
:CALibration:ENTer
:CALibration:EXIT
I think Rigol has been using this type of protection in the latest equipments so that one doesn't execute unwanted calibrations. My guess...
Edit: These commands are only for the analog channels!
Do you do a :LA:ACTive command before the calib to choose the specific digital channel before setting the delay?
Got two logic pods and the main board done. With just the main board in the scope, I have a lot of noise as mentioned above. But when I plugged my pods in, they light up for a second and then turn back off. I think either I messed up all of my USB connections since I tried the majority of them, or the USB-C cable I have lying around is not a Gen-2 so it may not work correctly. I may get a chance between now and next week to take a peek, otherwise I'll probably get it running by mid-October.
One change I had to make was using an 1uF electrolytic cap for C11 because I must have already packed up my 1uF ceramic caps. I've got it in polarity correct ( ) so my assumption was that it will work the same in this situation. Would love to hear some feedback whether or not it's true. From the schematic it looks like the STM32F030F4P6 and all the associated passives are for the OLED screen. Is it possible that they're causing issues if I don't have the screen hooked up yet?
I'll clean up the flux and upload a photo later when I get a chance.