Dear friends,
nippur72 and I have the pleasure to share with you our latest project:
Apple-1 microSD Storage Card.
Main features:
- Compatible with Originals/Replicas
- Command Line Interface MS-DOS/Linux style
- fast loading/saving of INTEGER BASIC / ML / etc. programs
- full support of AppleSoft LITE BASIC with dedicated load/save/menu commands
- FAT32 filesystem of the SD card, directories/subdirectories supported
- compatible with CFFA1/PRODOS naming system (CiderPress not needed)
- very large storage capacity
- built-in full RAM expansion, with possibility to replace the on-board RAM
- full implementation of the VIA 65C22, also available for your projects
- 8 kB EEPROM + ATmega328P for a fast & friendly interface
- open source firmware for future updates and improvements
Complete documentation:
https://p-l4b.github.io/sdcard/
Demo video:
Enjoy! :-)
This looks very amazing, something I need for my Replica 1! Are there units or kits available?
Nice work. While not "authentic", it certainly fills a big usability gap and will make playing with Apple 1 replicas a lot more approachable.
Hi skate323k137,
I sent you a personal message with all the details, but I'm afraid the board is not out-of-the-box-compatible with your Replica-1 (if we're talking about the one made by Briel Computers).
All my projects ( https://p-l4b.github.io/ ) are compatible with Originals and 1:1 Replicas (full hardware): you are actually the first Replica-1 owner I come in contact with. :-)
I had a look at the manuals and, at a first glance, there is definitely a RAM conflict: both my board and Replica-1 allocate the first 32kB.
I could be wrong, but apparently it's not possible to set the Replica-1 to reproduce the original RAM mapping, just as it's not possible for my board to completely deallocate the RAM expansion.
(This is something I'll eventually think about in future batches).
With the current version of the PCB, deallocating the RAM is definitely possible though.
I'm evaluating which is the best option without the need to cut tracks or make jumpers, if possible.
In fact, I am afraid that the mere removal of the RAM from its socket, although effective, would bring noise on the data BUS because of the transceivers that would be engaged anyway by decoding address logic.
But maybe on the Replica-1 this is not a problem, because of its more modern HW... It's hard to tell.
The Replica-1 allocation of EPROM space from $E000 to $FFFF should not be a problem for the microSD card (INTEGER Basic will always be available).
Also the addressing space "reserved" for the CFFA1 $8000-$AFFF is perfectly compatible with microSD card + built-in 6522.
At the moment I am not able to determine other differences that could cause malfunctions, such as the presence/absence of signals like phi(x), refresh etc. nor the degree of "fidelity to the original" of the signals on the expansion connector...
I would really like to figure out the degree of compatibility of my projects with the Replica-1, but I am aware that it is not easy...
I'll keep you informed on the possibility to resolve at least the RAM conflict, if you like.
:-)
Regards,
Claudio - P-LAB
ps thank you 8BitHeaven ! :-)
Thank you so much for the thoughtful reply!
Yes, I am indeed talking about the Replica 1 plus from Briel. It was a fun soldering project. I have changed it to a 65c02 for lessening power consumption and it seems to like that.
I have changed the EPROM for one 2x the size, I am going to bridge the upper address line to the R1+ breadboard section, and put a toggle on it. I have not modified the rom yet but I have tested dumping and stacking the firmware bin 2x and using it with the upper address line high on the new ROM. This will allow me 2 boot ROMs though if needed.
Kindly keep me up to date, no rush, but having a solution like this would be fun (even if it's some work for me as well).
For the RAM related thing, I may have found a pretty handy work-around-solution.
It involves lifting a couple of pins of the address decoder (socketed), no tracks to cut, no wires to add.
The removable RAM configuration jumpers need to be pulled as well (which is already possible by design).
I'll forward you all the details, of course.
As I said, I don't know if there could be other obstacles, but it is mandatory that both the WOZ monitor code and the PIA addressing (and usage) are consistent with the original.
I had a quick look at the schematic of the Replica-1 Plus:
http://retro.hansotten.nl/uploads/apple1/r1plus%20schematics.pdf
Apparently all the key signals are in place on the edge connector, but I have a concern about the /REFRESH signal (edge conn. pin 1): I doubt it is connected to anything.
This signal has no reason to exist on the Replica-1 (which uses static RAM), it is however used by my board.
"IF" it is not connected to anything, as I think it is, you may need to tie that pin to +5V.
I unfortunately don't have the chance to investigate further any other sources of incompatibility, but at least it's a start! :-)
Thanks and have a nice day,
Claudio
Hi Claudio,
I woundered when you would publish that, as I have seen the ROM in the EMU.
But I expected it to be somekind of Addon so nice to see it is a fuly integrated card.
Best
Stefan
Hi Stefan! :-)
Thank you for your comment... Yeah, the design and the tests with @nippur72 took a while!
Even though the development has been done on Juke-Box hardware, a fully integrated board was absolutely necessary.
n fact, an add-on would have been definitely horrible to look at and not very practical, as you can see... :-)
Cheers,
C.
20220428_172222.jpg
Hi all,
as anticipated by skate323k137 (a big thank you!!), with just a few mods it is possible to use Apple-1 microSD storage card with Briel Computers Replica-1 Plus.
Reference guide has been uploaded to the usual GitHub page:
https://p-l4b.github.io/sdcard/
Modifications refer to units already in circulation (PCB v1.13) or currently in preparation (PCB v1.16).
Further changes or improvements will be promptly communicated!
Enjoy! :-)
Claudio - P-LAB
It was my pleasure to help test. I am so happy with your willingness to work with this replica.
For those who have not used the P-LAB card, I must say it is very impressive. The time savings in loading a program versus a serial terminal is infinite, programs that took 30-300 seconds to transfer from text document are able to load from SD card in just a couple of seconds.
As small of a thing for some people as it may be, for me probably the nicest thing is the OS and user interface. It is simple but thoughtful and does what you need. Little things like proper backspace support, recognizing both 'dir' and 'ls' as valid commands, and support for multiple directories, make the Apple 1 seem like a computer several years ahead of its time.
For curiosity, do you know when the next revision of the card may be done with manufacutre and made available?
Cheers,
Alex
Alex,
thank YOU for the opportunity you gave me to make the board working with Replica-1 as well! :-D
The next boards (version 1.18) will have jumpers for memory deallocation, various optimizations, and a solution for the additional jumper on Replica-1, which will therefore no longer be necessary.
If no problems emerge with this test batch they will be in production very soon.... :-)
I have included all the informations on this topic in the document "
Briel Computers REPLICA-1 compatibility modifications"
available here: https://p-l4b.github.io/sdcard/Enjoy! :-)
Claudio
Great work everyone!
I am buying a Replica 1 plus and would be greatful if you can sell me one when its ready!
Thanks!
Bill
I am also building an Apple 1 :)
Hi retro_bill,
I've just sent you a PM with all the details.
Thank you!
cheers,
Claudio - P-LAB
Mille Gratze Claudio!
Sono pagato :)
Bill
Grazie a te! :-)
Ciao!
Are you still selling the Apple 1 SD card reader? If not is there some way I can get a schematic of it.
Thanks in advance,
Gman69
Hi Gman69,
sure, I've just PM'd you all the details.
Best Regards,
Claudio - P-LAB
Hi Claudio,
I have sent PM
Best Regards
Tulack
Hola Tulack and welcome,
I've just sent you a PM. :-)
Best Regards & thank you,
Claudio - P-LAB