Re: SD2IEC

On 5/6/2026 7:32 AM, ruud_at_baltissen.org wrote:
> Hallo allemaal,
>
>
> I recently found a home made SD2IEC that was given me some time ago 
> and that I had lost. I wanted to document it but then I found out I 
> cannot read the contents of it ATmega1284. Searching the Internet I 
> found various different designs of the SD2IEC, either with 1284 or 
> 644. I think I found a schematic that looks like the one I have. But 
> just the schematic, not the firmware. I also found schematics of a 
> SD2IEC with LCD but again, no firmware. I found ZIPs with firmware for 
> 644 and 1284 equipped SD2IECs but knowing already three different 
> schematics exist, different in the way pins are used for the IEC 
> signals for example, which one fits with my design?
>
> My question is simple: who can point me to schematic and matching 
> firmware? With these two I should be able to create my own working 
> SD2IEC. Preferably with the 1284 as I have laying the around and, if 
> possible, the LCD version.
>
>
> I also found a ROM for the C64 that can handle SD2IEC using various 
> keys like the function keys. Haven't tried it yet, will do that one of 
> these days. But again, no documentation except some source code. It is 
> badly documented but good enough for me to see if I can disassemble 
> it. Also here: any known documentation is welcome!
>
>
> Thank you very much in advance!
>
>
Here's the site for binaries and the Source TGZ.  I assume that's where 
you got the ZIP bins from.

You can dload and extract the source, but it's probably easier to just 
peruse online at one of the forks' github repos:

https://github.com/thierer/sd2iec/blob/master/src/avr/arch-config.h

Check your schematic against the big IF statement in this file for 
mappings (DATA, CLK, ATN, etc.)  Then, once you find the mapping, check 
the CONFIG_HARDWARE_VARIANT number.

Then, with that number, check this dir:

https://github.com/thierer/sd2iec/tree/master/configs

The variant with your number is the name of your HW design.

And, you can roll your own just by adding an else in that config.h file 
and creating another config file.


-- 
Jim Brain
brain_at_jbrain.com
www.jbrain.com