What does flashing do?


 

Darren C.

TVWBB Pro
When the LinkMeter v9 image is flashed to the HMv4, where does it go? Is it being flashed to the HM PCB or, is it overwriting part of the OpenWRT image?
 
The ATMega on the HM board is a mini-computer in it's own right.
It does the measurement, fan % calculation, PID control etc. It sends data to the RasPi, which then does the graphing, webpage server etc.

When you 'flash', you overwrite the OS on the ATMega AVR by sending info from the RasPi to the HM- just like installing windows or linux.
 
That is pretty much exactly what I thought, which is why I am confused.

When I first built my HM, I already owned a Pi. So, I installed OpenWRT, set up networking, and played around with it while I was waiting for the HM parts to arrive. When I got everything assembled and booted it up, everything seemed like it was working fine. I didn't have to flash anything. Maybe first boot flashes it for you when it detects the HM. Now that I think about it, that's probably what is happening.
 
That is pretty much exactly what I thought, which is why I am confused.

When I first built my HM, I already owned a Pi. So, I installed OpenWRT, set up networking, and played around with it while I was waiting for the HM parts to arrive. When I got everything assembled and booted it up, everything seemed like it was working fine. I didn't have to flash anything. Maybe first boot flashes it for you when it detects the HM. Now that I think about it, that's probably what is happening.

My understanding is that if there is not an image already flashed it will flash it.
 
Yeah it tries to install the firmware if a blank chip is detected on the first boot. Blank meaning the AVR fuse bits are the factory defaults. On subsequent boots, if the linkmeterd doesn't get any data from HeaterMeter for a certain amount of time, it shuts down and tries to reflash the chip as well.
 

 

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