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Old 11th May 2018, 1:13 am   #5
Slothie
Octode
 
Join Date: Apr 2018
Location: Newbury, Berkshire, UK.
Posts: 1,287
Default Re: Tesla MH74S571 programming.

Well that's interesting because the MH74S571 doesn't have a CS2 pin, and looking at the code, it only programs bits that need to be '1' by pulling them low during the programming cycle... Implying a unprogrammed chip should be all '0's! Bits not being programmed are pulled hi to 5v. The chip select is pulled low for 4mS to program the bit. The 21v programming voltage is applied to Vcc (Ucc?) pin.

Sounds like a completely different chip!
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