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Old 12th Sep 2018, 3:37 pm   #59
kazzawozza
Retired Dormant Member
 
Join Date: Aug 2018
Location: Llandudno, Conwy, Wales, UK.
Posts: 5
Default Re: Tesla MH74S571 programming.

Hello again,

Over on another forum I've been told that a PROM programmer configured for a Philips 82S131 can program an MH74S571. The person in question says they've programmed "lots of that [Czech] part" with a Logical Devices Chipmaster. See the forum thread here.

Looking at the programming procedure for the Philips 82S131, it is apparently programmed with VCC at 8.75V and the output bit at 17V, pulsing /CE to program. The MH74S571 expects the output bit to be grounded, and VCC at 10.5V, pulsing /CE to program. Somewhat different techniques, but I can see how the techniques could be compatible, as in both instances the non-programmed bits will be at 5V, thus within ~5V of VCC (or floating, in which case there'll be no current flowing). The significant difference appears to be the polarity of the effective voltage (and direction of current) used to blow the fuses.
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