I expanded my clock, and added a simple animation using 7219 and an 8x8 matrix, basically a rotating line with 15 frames of sprites, works great, except it stops!
Yesterday I rigged up a second 7219 with 2x 4digit 7seg display, also works fine!
then i connected both in parellel, and it still works fine, both displays run test programs using the led library, and both work at the same time!
So I re-run my clock, after some time (30 mins?) one or both displays stop working, if I reset the arduino it works again, the clock on the third display never stops!
The displays all use mod on a counter to decide when to trigger or which frame to display, and the counter resets after 1500 x 50 ms so there is no overflow.
Still having problems, I removed the Matrix, I now just have 2x 4digit 7 seg displays connected to a MAX7219 running a simple counter loop I got to 3000000 last night and the last 4 digits blanked, after a fer minutes it came back on, this morning I woke up and the display showed 8.8.8.8.8.8.8.8. with no explination for it, a quick press of the reset button and we are back under way.
Does anybody else have problems (I am running the arduino off an external 500ma 9v powersupply) and I have the display dimmed to the minimum using software.
Lol, this is annoying now, tried test patterns cycling all digits blank - 9, no problems ran for 2 hours, fast alternating between 6 & 9 no problems again, I thought current drain once more digits where showing might be the problem, now trying a slow alternate between 6 & 9 on all digits to see if that causes blanking.
That could well be the problem, I do have a 10uf and 100nf capacitors on the power to the 7219 already, but I am now testing with various update frequencies, the original updated at the max the Arduino could muster, which would point to you being correct about the problem!
Could it be a hard to find or obscure code issue? I've searched for problems (on website programming) for days, only to find it was a missing dot, or a missing semicolon... most often it would be a lower case L instead of an upper case I ... No clue if it could be a code problem or a hardware problem... but if it seems to work most of the time, and you have proper decoupling in place, in my limited electronics experience, it would have to be a software bug...
but I'm new, so take my advice with a grain of salt
Well you cant get simpler than a for loop, given that the display changes brightness and changes to all 8's or half of the display blanks, or it just all blanks I ruled out the software.
As I speak its been generating random numbers for 5 hours with no problems, with no delay! I think I will try the counter again and see if it still happens, perhaps I needed some burn in time!!!!
