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Firmware wont retain steps/mm setting

Posted: Sat Jun 04, 2016 1:34 am
by Farr0wn3d
I installed a titan last night and have it printing well. I did the PID autotune, changed the steps/mm in the firmware and reflashed it, reset the z height and for whatever reason when I check the steps per mm on the LCD it reverts back to the original value after every print. I could just adjust the multiplier in S3D but I want to do it right.

Anyone have any suggestions?

Re: Firmware wont retain steps/mm setting

Posted: Sat Jun 04, 2016 3:52 pm
by Matt_Sharkey
you are using M500 to save to the firmware correct? or are you editing your firmware manually?

Re: Firmware wont retain steps/mm setting

Posted: Sat Jun 04, 2016 8:46 pm
by Farr0wn3d
I was editing the firmware in the arduino runtime and then uploading it to the printer but for the first time ever in my experience it didnt wanna hold the parameters unless I issued an M500 command. Issuing the M500 made the difference though. Thanks for the reply.

Re: Firmware wont retain steps/mm setting

Posted: Sun Jun 05, 2016 5:42 pm
by ednisley
Farr0wn3d wrote:for the first time ever in my experience it didnt wanna hold the parameters unless I issued an M500 command
I think that's the new normal.

IIRC, the firmware now verifies that the firmware version stored in the EEPROM matches the current version (which means the EEPROM data layout will be appropriate) and the data has a valid checksum. If that comes up roses, then it reads & uses the EEPROM data. Otherwise, the baked-in firmware settings prevail.

That's what you want to happen during normal operation: valid EEPROM data overrules the firmware values, presumably because you previously stored the settings you want in EEPROM.

At least some earlier firmware versions would read & use whatever garbage it found in the EEPROM without any checking, often leading to heartache & confusion. This is a definite improvement, even if it's surprising the first time around...

Re: Firmware wont retain steps/mm setting

Posted: Sun Jun 05, 2016 10:51 pm
by Farr0wn3d
Thanks Ed, thats good to know. I'll get in the habit of throwing an M500 command by default when making changes in any case