Give the opportunity to set the polarity to 1 and not 0.

[emmanuelthome]

Given that the MAX31865 can deal with both, it seems reasonable to expose this in the interface.

[jposada202020]

@emmanuelthome want to try to test this changes, not very familiar with the hardware, so, if we need to test this change, setting the polarity property to 1, we could invert the cable connections?
Thanks

[emmanuelthome]

Yes, connect to a clock that idles high.

I presume that you can bit-bang this using gpio pins, too. this would require the spidevice to be handled directly from python so that you can use any signal pins you like, as opposed to using the microcontroller hardware spi. Not sure if there's a testing mechanism to do that.

[jposada202020]

Ok, understood, according to this it seems that I need to do some reading also, will do over the weekend, thanks for your contribution :) keep you posted with my results or questions.

[jposada202020]

@emmanuelthome my bad, so while reading the datasheet I discovered that inverted the last two numbers, So I have the MAX31856. However this will be solved next week, and I will have (sure, sure) the MAX31865. So I could review. sorry :)

[jposada202020]

sooooo I have good news and bad news, good news is I received the breakout, bad news is that either I fried it or I solder it wrong.
I kept getting

Temperature: -115.990C
Temperature: 463.521C
Temperature: -115.990C

all the time
So I do not have the means to test this, so hopefully other person could test this.. Thanks

[FoamyGuy]

Looks good to me. Tested successfully with Feather RP2040 and simpletest script, confirmed new polarity argument that gets passed to SPIDevice constructor.