Hey there!
Since whdload for the Amiga needs a lot of RAM for some games and my Amiga only sports a meager 2MB in total I searched for a way to get some more.
I stumpled upon the pcmcia-Slot for expansion pretty soon and had a look for expansion cards.
But damn, these are expensive! Even decade old sram cards for the pcmcia slot still cost a pretty penny these days.
But apparently some nifty guys from poland designed a new sram card, called the “Sakura 4MB PCMCIA SRAM”. You can find a link to their website here: https://sakura-it.pl/sram.php
Unfortunatly they stopped producing the cards a while ago. But being awesome dudes they offer the sources on github! So I decided to make an expension card by myself, using their sources.
But bummer, they are using parts you can’t find in 2018. Sure, you can get them from china salvaged from devices but meh, I like to get new parts. So I revised the circuit. It wasn’t that difficult, I had to change the sram IC, one other IC and the pcmcia connector. And since some guy said that the newest revision of the pcb on github seems to have problems I settled on the version 2.1. of the pcb as a base for the new revision.
The last thing to keep in mind is that pcmcia cards have to be exactly 3mm in height to fit into a pcmcia slot. I just designed three 1mm pcbs sandwiched together, you’ll see what I mean in the photos below. It would be nice to have a metal sheet to shield the pcb, but unfortunatly thats out of my realm of possibilities.
To sum things up here are some pictures of the build and a link to the sources:
Sources on github: https://github.com/jensma/ppa-pcmcia-sram/tree/master/board/v2.12018
Hello. I’ve got an assembled Sakura board, but i’m getting “write protectected” message from prepcard util if i initialize it as a disk or as a ram. At boot time instead, with ATK, i see no fast ram..
Any advice? Thanks a lot,
Stefano
Hey there! Unfortunatly I have no clue 🙁 Im out of the “Amiga-game” for some years 🙁
With whdload popularity you could sell hundreds or thousands on eBay.
Hello,
Since my first message, I designed my own board and ordered the PCB.
Today I assembled it.
And I can confirm that it works fine in my A600 without this feature !
I will test it some more then I have to clean up my work in order to share it.
GKar, you are right, the answer was in the schematic. I need to confirm that it is the same for the A1200 however I have no doubt about it.
Tanks a lot !
Hello.
I found your projects while searching for Amiga hardware stuff on OSHpark.
I am interested in building such a RAM expansion for my Amiga. However I plan to use CY62167E SRAM chips that are 5v and would not need any logic level converter. And also reuse the case and connectors from PCMCIA to CF adapters, that are still cheap and readily available.
When limited to this application, Amiga and RAM only, I am actually wondering if the “odd byte on d7-d0” feature is necessary, since it would really simplify the design with just one or two RAM chips and the CPLD.
Considering that this feature is not available when Fast ram is installed internally in the machine, I would like to believe that it is actually not used.
Since you have built these boards : by chance, did you happen to test and confirm this assumption (by not installing IC3A in your design) ?
Hey there!
Unfortunatly I can’t help you with this. I don’t have any more of the sram cards right now and can’t do any tests 🙁
Hi FLACO,
I have just started looking into this myself. Have you already made any progress? Looking at the schematic
(https://www.amigawiki.org/dnl/schematics/A600_R2.pdf, page 12),
it seems like ‘a0’ can only be high when ‘reg’ is low, so the “odd byte on d7-d0” feature should not be necessary.