Thermistor pin swap

[MateMago]

Hello everyone,

I am trying to upgrade my i3 Pro B to use 2 extruders. It mounts a GT2560 A+.
I flashed the i3 Pro C firmware, but the second thermistor input seems broken: it measures 198°C with no thermistor plugged.

- If i shortcut it measure something like 350°C
- if I plug the thermistor and heat up the hot end the temperature rises, but obviously its not a real measure.
- I thought it was a problem with the pullup resistor so I changed it with no luck.
- The resistance and voltage on the pins are 0.57KOhm and -0.56V (on the other input which works fine are 5.7KOhm and 4.90V).

To easy fix this problem without changing the board I was wondering if there are any other unused pins that I can use as thermistor input (changing the pins.h file). The only working solution I found is to renounce to the heated bed and use that input for the second extruder thermistor but I really don't want to. Thank you in advance for all the help.

[William]

Hi, I hope this can help you :http://www.geeetech.com/forum/viewtopic ... 13&t=17887

[MateMago]

I followed this guide william, but my problem is that the input for the second extruder thermistor is broken on the board, so I need another pin to use as for the input of the second thermistor. I know there are plenty of unused pins on the GT2560 a+, but I don't know which I can use as a thermistor input.

[_kaktus_]

Hi.


You need to plug in an analog input with ADC functionality.

You will find the controller board schematic and the µC data sheet helpful.

Alternatively, this forum.