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EBB36 vs SB2040

hbar

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Does anyone have any thoughts or preferences between on SB2040 vs EBB36? I have a PT1000 temp sensor that I would kind of like to use as intended with the MAX31865 on the EBB36 but I am wondering if I am missing out on something not as obvious on the SB2040 for something that isn't strictly required. Anyways would love to hear what people think. Thanks!
 
For sure the inputs on the SB2040 are not 5V safe, everything needs to be 3.3V. Not sure about the EBB36.
 
For sure the inputs on the SB2040 are not 5V safe, everything needs to be 3.3V. Not sure about the EBB36.
This pin diagram seems to indicate otherwise, all the end stops include 5v so I am assuming they gpio pins can take 5V, or am I misunderstanding? If so what are the implications?

The SB2040 has an option for switching the pullup resistor for better support of a PT1000.
Yeah I saw that, I wonder what effect it has on the accuracy of the probe as my understanding is that the MAX31865 helps with that.
 
This pin diagram seems to indicate otherwise, all the end stops include 5v so I am assuming they gpio pins can take 5V, or am I misunderstanding? If so what are the implications?


Yeah I saw that, I wonder what effect it has on the accuracy of the probe as my understanding is that the MAX31865 helps with that.
The Endstops may have 5V available but the GPIO pins on the RP2040 can't handle 5V.

An RP2040 (as on the SB2040) does not have that. Thats why it has an HV endstop which has a diode installed.
 
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HV Endstop: notice the red circled diode


Normal Endstop:

no diodes
Right, I think I got it now: the normal end stops signal with ground to the signal pin with a pullup resistor and they include a +5V for a status LED (or one does)? The HV end stop of course is meant for the inductive probes which signal with +VCC to signal pin? Assuming I am not using an inductive probe and my end stops will either be klicky (my current setup) or TAP (a possible future upgrade) then my understanding is that I can use the HV end stop for klicky or TAP. Is this correct? Are there any other gotchyas from this 3.3V gpio I should be aware of? Am I way off base in my understanding?
 
Yeah I saw that, I wonder what effect it has on the accuracy of the probe as my understanding is that the MAX31865 helps with that.
The MAX31865 is required for a PT100 but you can run a PT1000 into a normal analog pin on the MCU same as a thermistor. The pullup resistor value does change the calculation and you need to configure it in Klipper since it will be 1kΩ instead of the default of 4.7kΩ.
 
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