Re: Hiding code from the User...

From: Nicolas Welte (
Date: 2001-04-04 12:19:35 wrote:
> >Ultimax mode to map into the C64. This is why it needs the extra cable
> >attached to the HIRAM signal in the C64 to allow access to RAM at $e000. I
> I never new it needed an extra cable (never having seen a RAMlink in the
> physical)
> >There once was a thread in comp.sys.cbm about this cartridge, called >"epyx
> >fastload internals" or something like that. I think parts of the ROM >are
> >mapped into I/O space, and accesses to I/O space trigger a circuit that
> maps
> >in ROML for a certain time. After a timeout the ROM vanishes again. >Quite
> tricky :-)
> Indeed very tricky, I did a search for it but could find the reference. Does
> anyone have this article?

Here it is. Somehow that damn Google crippled the old Deja archive even more,
old postings are completely gone :-(

Maybe you can find the rest of the thread in CKB:

From: john/lori <>
Subject: Re: fastload cartridge internals?
Date: 20 Apr 1999 00:00:00 GMT
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>     Yes, it's available in my notes, aftr having just opened up an Epyx "Fast
> Load" cartridge to find out what goes on inside.


I opened mine up and traced the connections but had not started
to analyze it yet.

I found the same as you, except I have /ROML driving the capacitor
node throught the sixth buffer (/ROML drives both pins 11 and 1, and
pin 10 is tied to pins 4,6,8, the cap', and /EXROM)
And mine's got a 5.6K pullup on /OE (ROM 22)

Expansion Port    7407            ROM
--------- ----    ----    +5 VDC  ---
                        5.6K <     i---
                             <     I
                    I\       <     I
-------i            I \      I     I
       I            I  \     I     I
-I/O2  I------------I  /-----o-----I -G
       I 10      13 I /  12  I  22 I
       I            I/       I     I
       I                     I     I
       I            I\       I     !---
       I            I \      I
       I            I  \     I
-ROML  I-----o------I  /-----!
       I 11  I    1 I /  2
       I     I      I/
       I     I
       I     I      I\
       I     I      I \
       I     I      I  \
       I     i------I  /-----i
       I         11 I /  10  I
       I            I/       I
       I                     I
       I            I\       I
       I            I \      I
       I            I  \     I
-I/O1  I-----o------I  /-----o
       I 7   I    5 I /  6   I
       I     I      I/       I
       I     I               I
       I     I      I\       I
       I     I      I \      I
       I     I      I  \     I
       I     i------I  /-----o
       I          9 I /  8   I
       I            I/       I
       I                     I
       I            I\       I
       I            I \      I
       I            I  \     I
-RESET I------------I  /-----o
       I C        3 I /  4   I
       I            I/       I
       I                     I
       I                     I
-EXROM I---------------------o                 I 9                   I
-------i                     I
                          +  I
                    0.47   -----
                     uF      I
                             o GND

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