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I am having trouble with microcontrollers (STM32s mainly) on custom PCBs. I want to get an oscilloscope to help me solve these issues. Naturally budget is small so I want to know is if a 100 MHz oscilloscope with 1 gigasamples good enough for to help me debug.

I'm not doing anything too fancy, just general IO, power supplies, low speed SPI, UART, I2C and CAN. I have a cheap logic analyzer so that's taken care of.

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  • \$\begingroup\$ For debugging serial buses and the like, that's good enough. Higher frequency scopes are mainly useful for RF signals. Best advice I can give otherwise is to not cheap out and buy some Chinese brand. That's what I did last time and I regret it, because the product quality is overall poor and the fan is so loud I'm just waiting for it to take off. Be prepared to spend somewhere between $1k - $2k for decent quality. \$\endgroup\$
    – Lundin
    Commented Mar 6 at 7:56
  • \$\begingroup\$ Whether or not a 100 MHz scope is good enough for your purpose is an opinion we can't know. It depends what problems you are having with them. Certanly a 100 MHz scope better than no scope at all. But as buses tend to have digital logic signals, a 100 MHz scope can't see a 20 MHz square wave as square wave any more as it can only see first 3 harmonics, it might be good for signals less than 10 MHz. Many MCUs, UARTs and SPI buses run faster than that. \$\endgroup\$
    – Justme
    Commented Mar 6 at 8:03
  • \$\begingroup\$ Calvin, the cheapest stuff is noisy, funky, and won't meet the specs they tell you about. But a dual channel with signal generation and multimeter is under USD80 (The Zoyi ZT-703S.) And battery-powered, which can be handy. The next step up may be Rigol or a Digilent unit. Both are good quality. But now up around USD300-USD500. Used, consider analog scopes from Tektronix. Or the HP 54645D MSO from HP. If you can afford high sample rates then by all means get one. I really do believe you should buy as much as you can afford to buy. And if you can consider it, then get an MSO. \$\endgroup\$
    – periblepsis
    Commented Mar 6 at 8:57
  • \$\begingroup\$ Calvin, But given your question -- sure, 100 MHz oscilloscope is enough for any of those protocols, so far as I can recall needing. I usually use an MSO for things like this. But I have used my 2245A 100 MHz Tek scope with success in every case I've applied it in cases you suggest. So 100 MHz should be okay. \$\endgroup\$
    – periblepsis
    Commented Mar 6 at 9:08
  • \$\begingroup\$ Don't forget update rate. HP, who sells high update rate scopes, made a nice appnote about why you should buy a high update rate scope. es-france.com/… \$\endgroup\$
    – bobflux
    Commented Mar 6 at 17:06

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