Re: Arduino + MCP9600 + thermocouple help needed

"James Waldby"  wrote in message news:utgg8s$21ao1$1@dont-email.me...
Yes, it's a good feature of battery-powered small cheap scopes that
they allow ungrounded operation.  As you note, some of them can't
capture I2C, which I didn't think about WRT the cheap scope I linked.
It does 250 KHz, not good enough for `Fast Mode` I2C at 400 KHz, let
alone the 3.4 MHz and 5 MHz versions of I2C.
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He could setClock() low enough for it. That scope would be fast enough for most of my hobby use, though I was spoiled by the $20,000 scope I ordered for digital radio data speeds. The company had one that went to 70GHz, with liquid helium cooled Josephson junction input amplifiers. They used it to develop military satellite uplinks, then parked it and its Dewar in the back of my lab. Since it lacked storage and even a trigger it wasn't generally useful. Mostly I used an HP8753 vector network analyzer instead of a scope above 1GHz.
Digital radio tech has made them very affordable:
https://nanovna.com/?page_id=21
Unlike many other communications protocols I2C doesn't depend on timing accuracy and the actual speed can be whatever suits the controller hardware and software, without bothering with timing. It is event-driven, the rising SCL clock edge indicates when to put SDA data on the bus, the falling edge of SCL when to read it, a microSecond or a day later. A program may impose an arbitrary timeout to detect a bad connection. In practice the upper speed limit depends on how quickly the pullup resistors can charge the capacitance of the interconnecting wires, which is why their length is limited.
https://docs.arduino.cc/learn/communication/wire/