Re: Mar1e gets (some) address LEDs #Homebrew #Electronics

Lee Hart

Paul Schmidt wrote:
there is no "Paul's Design" in regard to the ELF schematic. What I show is just
the same as the magazine article schematic, merely cleaned up and made neater,
with more descriptive comments and such. I did not change anything that I can recall in regard
to the way "MP" works.
That's correct. Paul's schematic is the same as the original PE Elf article. Both leave the RAM's /WE pin "floating" during the time the switch transitions between WriteEnable and WriteProtect.

The 1802 Membership Card includes a pullup resistor on RAM /WE, and I've never had a problem with phantom writes. Perhaps adding one will fix your problem? It's an easy thing to try!

Fools ignore complexity. Pragmatists suffer it. The wise avoid it.
Geniuses remove it. -- Alan Perlis, "Epigrams on Programming"
Lee Hart, 814 8th Ave N, Sartell MN 56377,

Join to automatically receive all group messages.