Re: Frankenstein UART Board #Serial #Homebrew

cmdrcosmac
 

Jeff,
The common monitors seem to be IDIOT and MCSMP.
Both should be available,(or pointers thereto) on Herb's Retrotechnology
website.

 Bear in mind that an 1802 system can program a 28xx EEPROM with no hardware
other than address mapping. You just use a Monitor to block-move the code
into the EEPROM in 64-byte chunks. You're doing the block-write instead
of the byte-write routine. As long as the CPU clock and the timing of the
move routine in the Monitor satisfy the chip's block-write timing thes will
work. I wrote a routine on a PC that does multiple block-moves of 64 bytes
from RAM to EEPROM, calculating the source and destination addresses and
sends commands to IDIOT. It pauses about 200 Ms. between chunks.
This used IDIOT with the 3-MHz (colorburst) CPU clock. The clock is not
critical as long as it's in-spec for the EEPROM.

 How to "get it in" in the first place?? That is an issue all Elf wranglers face.
On the Retrotechnology site are a few suggestions, most will need extra
hardware and something on a PC to send the code to some kind of loader
which is toggled into the Elf. Chuck Yakym and David Madole have done
work in this area. It would be nice if someone would make available
a programmed (E)EPROM with a monitor, to get a user started. I suggest
IDIOT because it is object-relocatable, easy to use, and historically
relevant. Once you have IDIOT you can load anything else.
-Chuck

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