Archimedes A410 - RPI 1MHZ interface

Hello, i have currently developed a little interface between a RPI4 and the 1MHZ bus of my AKA10 I/O Card used on my A410, I would like to create a ‘bridge’ to allow the keyboard, mouse, disks of my old A400 to be accessible by the RPI and on the other way, SDFS and FAT32FS (USB) be accessible from my old A410, so I could have best of both world. Does anybody already developed a DeviceFS driver to cope with the GPIO of the RPI to communicate a 8 bits stream ?

As a beginner in machine programming, I am a little bit puzzled…
Thanks for any help

Just saw this post, sorry.

So, one quick recomendation is, for all things retro RISC OS, you probably want to have a look at stardot forums, where many RISC OS retro enthusiasts hangs out and do all sorts of creative projects. Here the community seems to be a bit more into RISC OS 5 only and (to me) confusingly about the future of the RO 5 platform.

Now to you specific questions:

1) AFAIR, the AKA10 should be easy to control using OS_Byte (please note, vaguely remember), so I’d start to ensure you can do simple things with it first.

I would like to create a ‘bridge’ to allow the keyboard, mouse

This should be relatively easy, there are ways to “cpature” mouse and keys on RISC OS and surelly you can transfer those through the 1Mhz bus, but you’ll also need somethign on the other end to receive and interpreter as well as, well, reproduce those events. All of which depends on which OS you’re going to run on your PI.

disks of my old A400 to be accessible by the RPI and on the other way, SDFS and FAT32FS (USB) be accessible from my old A410,

Hummm this is definitely going to be a lot more challenging, and not sure how feasible in the short term. But then again, I have never tried such a thing, so there may be some way to use a serial protocol to achieve something alike and incredibly slow (if at all working). In the end the Commodore 64 used a similar approach to connect to the Floppy Disk Unit, it used a serial port and the Floppy Disk Unit was an actually 6502 based computer talking and tranfering data back to the C64.

But oh boy if it was slow lol

As a beginner in machine programming, I am a little bit puzzled…

You shoul dbe able to use C for this, but it will also take quite some good knowledge of RISC OS, the HW involved and writing Modules at the very minimal.

We have some introductory videos on coding on RISC OS which also show how to access the PI GPIO, but we haven’t touched yet making Modules and more advanced programming techniques. However if it can be of any help to start, here is the link to the channel:

https://www.youtube.com/channel/UCr4zW_z3WfBVBha3droh_rQ

Videos are made for all type of background knowledge, however we assume the viewer knows at least the basics of each programming language we use in the the videos.

Good luck with your adventure! :)

disks of my old A400 to be accessible by the RPI and on the other way, SDFS and FAT32FS (USB) be accessible from my old A410

Got a 10BASE-T network card for the 440? ShareFS is a thing… ;)

Hello again, thanks for the links to the videos, it will certainly help me for some topics. The goal is of course to use the RISCOS 5 platform on the pi side, keeping the same ‘archimedes’ feeling.
Bus interface is now build and I am testing all the signals, the routine for capturing mouse and keyboard on ARC side are done and ready to be passed through some ‘OS_Byte’ calls to FRED Area.
Once that is finished and controlled, I will return to the RISCOS5 side, to capture data from GPIO’s and emulate a ‘FRED’ memory space that I will use after to handle the received data.
Thanks already for your advices. I have no 10BASE-T card, but the goal is really to pass any information via 1Mhz bus so I keep everything ‘inside’ the A410 box, without external cables…
I already 3Dprinted a special backpanel to support the RPI 4. So actually, I can easily switch between vga entry and hdmi entry on the same monitor.
If anyone interested, just contact me I will provide ‘kicad’ files and other building infos…
Thanks everyone.

Hello, just a little update on my project. After playing with the 1Mhz bus, i found the very interesting articles on Podules designing from Theodore Markettos (http://www.markettos.org.uk/riscos/podules/), and I decided to change my design for a real Podule card, using also a HIGH SPEED 7130SA/LA 1K X 8 DUAL-PORT 7140SA/LA STATIC SRAM to act as a memory buffer between the A440 and the RPI, with this configuration, any two computers can write/read the memory in an asynchronous way (even if some handshaking are setup using L_int and R_Int signals from the IDT7130 device. By doing this, I don’t need anymore the AKA10 interface to be present for the 1Mhz BUS operation. I still have my previous design already done, but I don’t know how to share it on the forum, is it mandatory to setup a GitHub space for that and then only share the link ?

I have created a GitHub entry for this project, a first draft of the schematic is available as a png image, next files will follow shrortly
https://github.com/alow2004/Archimedes_RPI_DoublePort_RAM_Podule/tree/main

I already 3Dprinted a special backpanel to support the RPI 4.

If you’re looking for something “off the shelf”, we do have this: http://www.riscosbits.co.uk/pipod.htm – I guess just the bracket, or the bracket and adaptor would do?