Thanks as always, finally getting caught up on your videos. I have my electronics bench back up and running after a move and been spending all my time there. Still have a major mess to clean up, but working on projects instead. Oh, the spring thing. I put it on my scope probe to short out components next to where I'm trying to measure. LOL, just kidding, kinda
Hello tomtektest, thanks for your fine tutorials. I am learning very much from them. But I have two questions: 1. is it okay to use a copper wire for the DIY ground connector (I think yes, but not sure)? 2. Regarding the PLA2216 logic analyzer adapter, how much does the length of the wires affect the quality of the signal?
Generally copper is as good as anything. Some metals (like Silver) have lower resistance but for such a short lead the difference would not matter. The important thing is to minimize the reactive part (inductive or capacitive) since that varies with frequency. Anything that provides a very low resistance and minimal reactance will work. The longer the lead, the more inductance and capacitance it will have, so a short copper wire is better than a longer silver one. As to the Logic probe I could not discern if you were referring to the length of the wires from the head of the analyzer or the length of the ribbon cable between the MSO5000 and the head of the analyzer. The latter is fixed by Rigol and I would not recommend changing it without checking with Rigol technical support, but the wires from the head of the analyzer to the circuit under test can vary but the effect will depend on frequency. Like all transmissions lines, the wires from the head of the analyzer will present a complex frequency profile that becomes more important as the frequency increases. Below about 10 MHz you could probably use longer wires than those supplied with the PLA2216 but above that I would consider using twisted pairs for each signal and making sure that they are properly terminated at the Circuit under test if best signal integrity was needed. For general troubleshooting you could probably use longer wires up to around 40-50 MHz but signal integrity would degrade. Above 50 MHz even the supplied wires may be too long, depending on the impedance of the driving circuit. But I find the signal readable up to the full 70 MHZ frequency limit of the MSO5000 I own with the supplied wires on TTL and CMOS logic without any special termination. Hope this helps and there is a lot more about this sort of thing in the book "High Speed Digital Design" by Howard Johnson.
Thank you for the answer. I was referring to the wires you connect from the ribbon cable to the board you want to debug, but I was a bit worried after watching your video and the ones you recommended. Thanks to your answer I'm relieved
Another brilliant video thank you!
Thanks as always, finally getting caught up on your videos. I have my electronics bench back up and running after a move and been spending all my time there. Still have a major mess to clean up, but working on projects instead. Oh, the spring thing. I put it on my scope probe to short out components next to where I'm trying to measure. LOL, just kidding, kinda
At 10:53 the board on the left is just a very old Xilinx CPLD dev board. This device isn't an FPGA it is a CPLD.
Hello tomtektest,
thanks for your fine tutorials. I am learning very much from them.
But I have two questions:
1. is it okay to use a copper wire for the DIY ground connector (I think yes, but not sure)?
2. Regarding the PLA2216 logic analyzer adapter, how much does the length of the wires affect the quality of the signal?
Generally copper is as good as anything. Some metals (like Silver) have lower resistance but for such a short lead the difference would not matter. The important thing is to minimize the reactive part (inductive or capacitive) since that varies with frequency. Anything that provides a very low resistance and minimal reactance will work. The longer the lead, the more inductance and capacitance it will have, so a short copper wire is better than a longer silver one. As to the Logic probe I could not discern if you were referring to the length of the wires from the head of the analyzer or the length of the ribbon cable between the MSO5000 and the head of the analyzer. The latter is fixed by Rigol and I would not recommend changing it without checking with Rigol technical support, but the wires from the head of the analyzer to the circuit under test can vary but the effect will depend on frequency. Like all transmissions lines, the wires from the head of the analyzer will present a complex frequency profile that becomes more important as the frequency increases. Below about 10 MHz you could probably use longer wires than those supplied with the PLA2216 but above that I would consider using twisted pairs for each signal and making sure that they are properly terminated at the Circuit under test if best signal integrity was needed. For general troubleshooting you could probably use longer wires up to around 40-50 MHz but signal integrity would degrade. Above 50 MHz even the supplied wires may be too long, depending on the impedance of the driving circuit. But I find the signal readable up to the full 70 MHZ frequency limit of the MSO5000 I own with the supplied wires on TTL and CMOS logic without any special termination. Hope this helps and there is a lot more about this sort of thing in the book "High Speed Digital Design" by Howard Johnson.
Thank you for the answer. I was referring to the wires you connect from the ribbon cable to the board you want to debug, but I was a bit worried after watching your video and the ones you recommended. Thanks to your answer I'm relieved