George,
Have you had time to run the MaxFlex on a NiMH pack yet, that's where I experienced the flakey problems.
I still have two from the first run, one in a Tri-LED Mag using 2 Li-Ion cells and it's 90% stable. I'm only experience problems when I try and latch to the brightest setting sometimes it turns off in a few seconds but you can turn it right back on.
The other is driving (5xLuxIII's) from a 35Ah SLA, that set up has been rock solid stable from day one.
I don't know what was up with the NiMH packs, it still has me wondering as I tried several different holders and variations :shrug:
Later
Kelly
Hi Kelly,
No - I've run on a power supply - the issue isn't the battery type - it's the voltage/current/LED combination. Certain combinations create slightly more transients on the supply and due to the location of the bypass cap for the uController it was causing the controller to either crash or reset.
I had a rock solid set of crashing/reseting conditions on the bench and when I fixed the capacitor issue that board has been 100% solid at many voltage/current combinations.
That's all that was wrong with maxFlex from the get go - basically a transient on the supply crashing/reseting the uC. Now that it is resolved the board is solid. I've ported the latest UIF/UIP/UIB firmware from the nFlex/bFlex platform (the same code other than just a handful of instructions) so the firmware base is well proven as well.
And - the latching to high (causing a crash/reset in a few seconds) is EXACTLY the failure mode that this rework fixes. In fact that was the only failure mode...
I totally understand why it was crashing before and why the things I did on the bench to try and fix it actually made things worse. In hindsight it was obvious why it got worse - it just didn't "click" at the time. Basically it was the location of the ground side of the bypass capacitor - a noisy area of the ground plane. When I cut the ground plane on the edge of the PCB (sorta kinda forms a ring around the board) it made it fail 100% - basically ~12Hz strobe rate as it turned on, crashed/reset, turned off, restarted and repeated the cycle. Once I had it failing 100% I was able to probe some areas with my scope and the noise transients on the supply were then very obvious and what was needed to fix it even more obvious.
cheers,
george.