MAX31865 support (pt100/pt1000)

juulius · June 2016

hi repetier,

dont know if you are already on it but maby its a nice thing to have for the radds or other due board users.

i know that the arduino library already exists

Repetier · June 2016

No I'm not on it and not having the hardware for testing I also won't. But feel free to add it and send a patch. Search for

SUPPORT_MAX31855

which is similar. You could use that as an example on how to do it. I guess they only differ in formula.

juulius · June 2016

shall try.

im going to upgrade from ramps to radds but have 2 pt100... the breakoutboards from e3d dont work with radds

keep u updated

Repetier · June 2016

Hope it works. SPI is hopefully compatible with sd card SPI.

juulius · June 2016

shall try it first with the max31855 setup because interface is the same, then i can see what for values i get and change the formule according to the readings from the e3d board

Repetier · June 2016

Would be a easy start at least.

juulius · June 2016

oke i tried and tried but cant get it to work, also i can connect to the due but no information is coming out of it (spi problem i think)

this is the initialy code for the max31865

the first thing i saw was that it is somewhat the same to the max6675 the only thing is that i need to program it first on first time ussage and on error.

but the main problem i have is the spi (i think). i saw that i need to use hal::spiInit() i need a clock devide of 200 so i thought i need to set spiInit(6) but can de due go that low (also tried 2 because datasheet says its the same as max31855)

if (CPU=="AVR") SPI.setClockDivider(SPI_CLOCK_DIV128);
if (CPU=="DUE") SPI.setClockDivider(200);
SPI.setDataMode(SPI_MODE3);

if you have some sparetime left maby you could point me in the right way, that will be really helpfull

juulius · June 2016

also i saw that i posted this in the wrong category, can it be moved to the firmware side?

juulius · June 2016

owh i think i found out what the problem is.. i need to set the max31865 to use spi mode 3 but everything else is using mode 0 as i can see in hall.ccp

// Set SPI mode 0, clock, select not active after transfer, with delay between transfers

SPI_ConfigureNPCS(SPI0, SPI_CHAN, SPI_CSR_NCPHA |

SPI_CSR_CSAAT | SPI_CSR_SCBR(spiDueDividors[spiClock]) |

SPI_CSR_DLYBCT(1));

Repetier · June 2016

Can you change mode before and after 31865 access, so rest should work? Especially sd card would be tricky if it does not work.

juulius · June 2016

thought it would be a easy modification (not)

but even with no sensor my due is just denying communication with the host, if i upload the firmware with 100k epos everything works fine

dont know what is happening here

i use the x_max endstop as select device pin all the other endstops are on the x_min endstops

juulius · June 2016

solved the problem need to use programming port instead of native, now i can see it gets watchdog reset.

juulius · July 2016

tried again but doesnt want to work, changed spi chan to 3 (as i guess thats the channel or mode) and after communication back to 0.

the only thing i get is watchdog reset, no other communication.
runned it with only the source code of the max31865 and it works so i know that its not a pin issue.

i think i need some extra information about how the hall:spi works.

also is there a way to configure the max31865 on when the due first get power? now i have it before i get temperature readout so everytime its get called it will configure the max31865 first (has to do with the 3 or 4/2 wire setup)

im not a very skilled programmer so any help would be really helpfull.

MaxGyver · May 2017

Hey,

has anyone made progress regarding the max 31865 amplifier? I would realy like to upgrade my Printer with a RADDS 1.5 controller to use a PT100 sensor.

Cheers !

MAX31865 support (pt100/pt1000)

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