Using a PT100 MAX31865 (BIQU H2 v2 500) on SKR 3 EZ with Marlin

[EArcher]

First off sorry for the dump of information I've been looking at this stuff wayyy to long and I think it's getting to me. Also thanks for any help that can be provided.

 

Following the instructions here it seems pretty straightforward. Yet I've had no success. I've tried to follow both the guide here in the 31865 Manual which doesn't work and Marlin warns you the methods mentioned here are being depreciated.

I've also tried using the guide here in the H2 500c Manual. This one seems to be the more up to date instructions. When I compile the firmware using these instructions the terminal gives me the below WARN.

 

 

In file included from Marlin\src\libs\MAX31865.h:48,
from Marlin\src\libs\MAX31865.cpp:47:
Marlin\src\libs\../HAL/STM32/MarlinSPI.h: In constructor 'MarlinSPI::MarlinSPI()':
Marlin\src\libs\../HAL/STM32/MarlinSPI.h:55:27: warning: overflow in conversion from 'PinName' to 'pin_t' {aka 'short int'} changes value from 'NC' to '-1' [-Woverflow]
55 | MarlinSPI() : MarlinSPI(NC, NC, NC, NC) {} |
^~
Marlin\src\libs\../HAL/STM32/MarlinSPI.h:55:31: warning: overflow in conversion from 'PinName' to 'pin_t' {aka 'short int'} changes value from 'NC' to '-1' [-Woverflow]
55 | MarlinSPI() : MarlinSPI(NC, NC, NC, NC) {} |
^~
Marlin\src\libs\../HAL/STM32/MarlinSPI.h:55:35: warning: overflow in conversion from 'PinName' to 'pin_t' {aka 'short int'} changes value from 'NC' to '-1' [-Woverflow]
55 | MarlinSPI() : MarlinSPI(NC, NC, NC, NC) {} |
^~
Marlin\src\libs\../HAL/STM32/MarlinSPI.h:55:39: warning: overflow in conversion from 'PinName' to 'pin_t' {aka 'short int'} changes value from 'NC' to '-1' [-Woverflow]
55 | MarlinSPI() : MarlinSPI(NC, NC, NC, NC) {} | ^~
If I ignore the WARN and flash the firmware onto the printer anyway I get this message on the screen "Err: MINTEMP: E1 PRINTER HALTED Please reset" and I'm forced to shut down the printer.

 

General setup/info

• I'm using a BTT SKR3 EZ board (User Manual) with 2209EZ drivers
• Using Marlin bugfix 2.1.x from 9/10/22
• I have the MAX31865 in the E1 stepper slot Using the 2-wire, PT100 thermistor included with the BIQU H2 500c kit.
• I have confirmed the DIP selections as 1,2,3 = ON & 4 = OFF

 

Troubleshooting I have tried

• I measured the resistance across the thermistor with a multi-meter and it's showing 110ohms I think it's OK there.
• At one pointed I commented out the //#define IGNORE_THERMOCOUPLE_ERRORS line from the temperature.cpp file and that stopped the printer from screaming on startup. It was still showing an error for the hotend temp though. Actually it was showing a temp of 989c
   

I looked at these Marlin issues for ideas but they all seem resolved and nothing I found there could correct my issues.

• https://github.com/MarlinFirmware/Marlin/issues/24513
• https://github.com/MarlinFirmware/Marlin/issues/23439
• https://github.com/MarlinFirmware/Marlin/issues/22526
• https://github.com/MarlinFirmware/Marlin/issues/22346

 

This is from Pronterface when I set the MAX31865 to debug
 

Connecting...
Printer is now online.
MAX31865 RTD MSB:66 LSB:60
MAX31865 bias voltage enabled
MAX31865 1 shot mode enabled
MAX31865 RTD MSB:66 LSB:60
MAX31865 bias voltage enabled
MAX31865 1 shot mode enabled
MAX31865 RTD MSB:66 LSB:60
MAX31865 bias voltage enabled
MAX31865 1 shot mode enabled
MAX31865 RTD MSB:66 LSB:60
MAX31865 bias voltage enabled
MAX31865 1 shot mode enabled
MAX31865 RTD MSB:66 LSB:60
MAX31865 bias voltage enabled
MAX31865 1 shot mode enabled
MAX31865 RTD MSB:66 LSB:58
MAX31865 bias voltage enabled
MAX31865 1 shot mode enabled
MAX31865 RTD MSB:66 LSB:58
MAX31865 bias voltage enabled
MAX31865 1 shot mode enabled
MAX31865 RTD MSB:66 LSB:60
MAX31865 bias voltage enabled
MAX31865 1 shot mode enabled
MAX31865 RTD MSB:66 LSB:58
MAX31865 bias voltage enabled
MAX31865 1 shot mode enabled
MAX31865 RTD MSB:66 LSB:60
MAX31865 bias voltage enabled
MAX31865 1 shot mode enabled
MAX31865 RTD MSB:66 LSB:60
MAX31865 bias voltage enabled
MAX31865 1 shot mode enabled
MAX31865 RTD MSB:66 LSB:60
MAX31865 bias voltage enabled
MAX31865 1 shot mode enabled
MAX31865 RTD MSB:66 LSB:60
MAX31865 bias voltage enabled
MAX31865 1 shot mode enabled
MAX31865 RTD MSB:66 LSB:60
MAX31865 bias voltage enabled
MAX31865 1 shot mode enabled
MAX31865 RTD MSB:66 LSB:60
MAX31865 bias voltage enabled
MAX31865 1 shot mode enabled
MAX31865 RTD MSB:66 LSB:60
MAX31865 bias voltage enabled
MAX31865 1 shot mode enabled
MAX31865 RTD MSB:66 LSB:60
MAX31865 bias voltage enabled
MAX31865 1 shot mode enabled
MAX31865 RTD MSB:66 LSB:60
MAX31865 bias voltage enabled
MAX31865 1 shot mode enabled
MAX31865 RTD MSB:66 LSB:60
MAX31865 bias voltage enabled
MAX31865 1 shot mode enabled
MAX31865 RTD MSB:66 LSB:60
MAX31865 bias voltage enabled
MAX31865 1 shot mode enabled
MAX31865 RTD MSB:66 LSB:60
MAX31865 bias voltage enabled
MAX31865 1 shot mode enabled 

 

 

Additional information

• https://www.makenprint.uk/3d-printing/3d-printing-guides/3d-printer-accessory-guides/btt-max31865-module-set-up/#BTT-SKR-V2

• https://docs.vorondesign.com/community/electronics/xbst_/PT100.html

• https://www.youtube.com/watch?v=a4qoQo7FNbQ

[Salsped]

I am having the exact same problem but with a different board. I believe I have narrowed the problem down to the TMC drivers but beyond that, I cannot get those working or implemented properly.

Have you been able to find a fix for this problem?