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Old 29th Nov 2022, 1:00 am   #18
Mark1960
Octode
 
Join Date: Mar 2020
Location: Kitchener, Ontario, Canada
Posts: 1,264
Default Re: Tesla Programmer

I think I was reading the wrong programming algorithm, but still worth checking what happens to the pins for bits that are not being programmed when Vcc is raised to 10.5v. The transistors pulling the pins to ground need to sink 150mA, so if the outputs are pulled up to 10.5v when Vcc is increased this could be quite risky for the 8255.

I’ve heard that 8255s are in short supply recently, not sure if that is another issue.
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