Hallo everyone, i have made this board and when i connect it to the arduino the IC1 doesn't work.
I have also added an on-breadboard level shifter for clk channel and only ic2 works. I also connected a third max31855 from another board i hade made and it's working. I mean all together 2 of 3 are working and i can read their temps fine.
Where is the problem? Thanks!
I have checked different ic's, not the problem.
So, if you swap in firmware CS1 and CS2, does the IC1 work on CS2? Does IC2 work on CS1?
This is a divide-and-conquer opportunity.
Ray
Still only ic2 works.
mantzas:
Still only ic2 works.
Without further testing, IC1 would seem suspect.
As I understand,
IC2 always works, with CS1 or CS2.
IC1 nevers works, with CS2 or CS1
Can the 3rd 31855 be wired as if it were CS1? That would prove or disprove a bad chip.
Ray
All chips have been replaced with good working ones.
Still same results. Something is wrong with my circuit and i dont know what.
The actual pcb was checked with multimeter and is ok no faults in etching
Not to offend you, but your Arduino logic CS logic does recognize that CS is a /CS signal, that is it is active low.
6 CS Active-Low Chip Select. Set CS low to enable the serial interface.
This would mean, at a minimum, that your CS pin logic must have a pull-up resistor and I'm not sure if internal AVR weak pullup is satisfactory.
Also, this is a 3.3V chip, so how are you buffering the Arduino signals? Or, are you running an 8MHz 3.3V Arduino?
You stated:
I have also added an on-breadboard level shifter for clk channel and only ic2 works.
but gave no specific details.
You may want to search the forum for 31855 and see if others have had similar issues with connections such as pull-ups and how they have resolved the 5V to 3.3V logic conversion (there are several 'good' ways to approach this.)
Ray
No offense taken, I'm still a noob trying to understand!
The level shifter is the attached one.
I didn't know that i had to use pull ups. Thanks for the tip.
I have searched around a lot and have found different answers. I have seen circuits for the 31855 with level shifters, with voltage dividers, with diodes and I don't know what to do.
Anyway i have ordered some soic adapters so I can experiment on the breadboard before trying another pcb.
Thanks for the help!
Just as a sanity check, here is test code and schematics for dual and quad 31855 breakouts.
Good luck
Yes I have seen them, they use the voltage divider approach.
Anyway when the adapters arrive I'll do extensive breadboarding and I will report my findings.
Thanks for the help Ray.
