Question about reflashing firmware vs storing in EEPROM

I'm a total beginner, building my first printer. I may be jumping the gun a little bit asking this, but I'm a little confused about something.

Reading the various calibration guides, and calibration videos, I seem to constantly see the need to reflash firmware when making changes. Like you measure your steps per mm, and then reflash the firmware. Measure your extruder settings, make adjustments and reflash the firmware.

I'm wondering why it works this way, instead of just having calibration values, and other variables like that written to eeprom. That way you just flash the firmware once, and never need to flash it again unless you upgrade, and could possibly make changes in real time and have them stick without the need to reboot.

I have heard that there are possibly EEPROM functions that can be activated to do this, but they don't appear to be mentioned much in the calibration guides, which seem focused on the reflash approach.

Edited 1 time(s). Last edit at 11/12/2014 08:51PM by scubaguy.

Most things are in eeprom. And you do just set them real time till you work out what you need.

You do need to set the board type and Thermistor types in firmware, most of the rest are all just gcodes and are saved to eeprom with m500

What's the problem with reflashing a firmware? This procedure takes about 5 seconds and you're done. It's essentially the same as when writing a file to an USB stick.

Compiling a firmware with fixed values allows a lot of computations and optimisations at compile time, so they don't waste precious CPU cycles at runtime. That's one of the major reasons why Teacup firmware is only half the size of Marlin or Repetier. Smaller binaries usually also mean faster execution.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

However reflashing experience may vary depending on your electronics and how they are mounted: When I had a printrboard Mk1 (which needs a jumper moving to reflash then back again afterwards) mounted in the base of my delta I found reflashing a right pain compared with changing EEPROM values

Cheers,
Robin.