ROM-Drive Update

["Terence J. Boldt" <apple2@cgocable.net>]

It boots!  Well, sort of.  I fixed up the code so it should work with
any ROM-drive size up to 512K and fixed the bug in the startup.  Apparently
the ProDOS code does run if you execute it at $801 and not $800.  Also,
I had trouble losing bytes once the address was higher.  It turns out that
it was drawing too much power causing the high outputs of the latches to
appear low to the ROM sometimes.  I jumpered the output enable and chip
enable together so that it will only turn on the ROM when it needs to.  This
fixed lots and suddenly it booted ProDOS 2.0.3 with BASIC 1.5.  It only
boots about 1 in 5 times.  It usually crashes after the ProDOS startup
screen or sometimes when starting BASIC.SYSTEM.  It only takes one wrong
byte to make it crash.  Reliability will be improved soon.  At least it's
on the right track.

-- Terence J. Boldt
mailto://apple2@cgocable.net
http://www.cgocable.net/~apple2