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Larson scanner extended troublshooting

Ive connected 5 scanners together. When I power them up, only one unit works. Ive triple checked my wiring, and cant find any mistakes. if I swap the processor from the one unit that is working to one of the non-working units, that unit will then work. Normally, I would assume that I have 4 defective processors, but that seems kinda bizzare. I purchased The 5 preprogrammed processors from EMSL, it seems highly unlikely to me that 4 out of the 5 processors I recieved are defective. Any ideas????


  • Are the boards all built up with the modifications required for the extended scanner?  Is it possible you have a chip with the default Larson firmware on it?
  • i Purchased 5 preprogrammed ATtiny2313 for Larson scanner-extended chips. Is there an "Easy" way to determine which firmware is on each chip? I have a USBTnyISP AVR PRogrammer, I'm just not very proficient with it. I'm also not sure what board build up you are referring to.
  • The article on using the extended firmware is here:
    If you are building the project up on the IX PCBs, there are several changes you need to make. Did you build your project taking those changes into account?
  • I followed the articles directions step by step, and it is certainly possible that I've made a mistake, but I've checked and re-check and I don't see any wiring mistakes.
  • Ok..... I cut all of the scanners apart, and looped the in's and out's. They each work fine by themselves. So I've rewired them all together, and now when I start them, the "pulse" starts a the 1st board from the left, and the 3rd board simultaneously. the pulse then run through the second board and stops. The 3rd board runs as if it was wired as a single board.I tried to insert a pic, but apparently I can't. I am at a loss.

  •  I swapped the chips from the 3rd board and the 5th (from left to right) and now it seems to work. I have no idea why? If I swap them back I get the same problem. I guess I will just leave them in the way they work, and not worry about WHY? (If I can sleep not knowing)
  • That's very odd. It sounds as though there may be wiring issues, or possibly issues with one of the sockets?
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