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HEPAX internal EPROM coding. (Maybe too) Techie post... ;-)
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HEPAX internal EPROM coding. (Maybe too) Techie post... ;-)
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HEPAX internal EPROM coding. (Maybe too) Techie post... ;-)
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10-10-2020, 04:46 PM
(This post was last modified: 10-11-2020 01:25 AM by Diego Diaz.)
Post: #3
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RE: HEPAX internal EPROM coding. (Maybe too) Techie post... ;-)
Hi Steen,
I see a potential source of problems to reprogram the EPROM directly on-board. Since the EPROM power (Vcc) is not separated for the RAM & ASIC chips, chances are that some spurious Address/Data signals conflicts with those comming from the programmer. But that's just a guess. The EPROM reading however has worked as expected for me. I've even written a short program to extract the 4 .ROM files from the EPROM dump .BIN and compared ok with currently available ones. Best wishes. Diego. [Edit] Correction: After checking the 27C256 datasheet it becomes evident that the EPROM cannot be programmed on-board since it has CE/ and OE/ tied together. 
"Do not suppose, check it twice." |
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HEPAX internal EPROM coding. (Maybe too) Techie post... ;-) - Diego Diaz - 10-10-2020, 09:35 AM
RE: HEPAX internal EPROM coding. (Maybe too) Techie post... ;-) - SteenPetersen - 10-10-2020, 03:53 PM
RE: HEPAX internal EPROM coding. (Maybe too) Techie post... ;-) - Diego Diaz - 10-10-2020 04:46 PM
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