Quote:
Originally Posted by SiriusHardware
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I can only admire Chris who only had to sacrifice one device to get to the point where he was confident of being able to programme further devices without any problems, although I understand he took the precaution of first only programming one bit at a time before progressing to whole nibbles, and so on.
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Quote:
Originally Posted by SiriusHardware
Speaking of which, I think Chris has a few 'used' MH74S571s for sale - useless for any normal purpose obviously, but a good 'practice target' for any Tesla programmer...
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I spoke to Chris earlier today about this. And he said he didn't actually waste any Tesla devices at all- As he only programmed locations that needed to be fuse-blown, when programmed (With intended code for Acorn system ?)
- Although I believe to start with, he could get it to blow fuses, as the initial transistors weren't saturating at low-enough voltage to gnd (may have been using ULN2003 etc darlington-drivers on first prototype)
He did, however, get a few National Semi casualties, whilst previously extending the original Acorn system programmer software to support the DM74S287 (as well as the original DM74S571) - But that was a software bug (I think it's all 6502 assembly-language) rather than a hardware issue.
So the only part-used (with no working code but still some unfused bits) for programmer testing he has for sale are some National Semi ones. But it may no longer be worth developing a programmer for these, as all previous main stockists no longer have any left, unless you already happen to have a number of blank ones.