Trying to get Acorn A5000 Keyboard working in macOS

Hello there,
A little while ago I bought a Acorn Archimedes A5000 keyboard that I was going to use in my primary setup to replace the magic keyboard I’m currently using. With the aid of “kbdbabel’s open A5000 → PS/2 protocol”:http://www.kbdbabel.org, I hoped to get this working in El Capitan. But I’ve hit a snag on the last line of the instructions on how to compile the code (“write kbdbabel_a5000_ps2_8051.bin on an empty 27C256 or AT89C2051”) I get the following error “usage: write user [tty]” which I don’t understand what this means in the context I’m trying to use the command. Currently the keyboard is plugged into my Hackintosh’s PS/2 port right now…

Does anyone have a suggestion on what to do or know any other way I can use this protocol? Everything has compiled successfully through the suggested assembler and has been merged into a .bin file, it’s just the final “write” step thats currently tripping me up. I would really appreciate any help that maybe given!
Thanks in advance,
Matthew

Thanks to the help of Nekochan, I’ve discovered that a “27C256” and “AT89C2051” are actually the controller chips inside the keyboard and I’ll need a EPROM burner to finish this mod!
This is starting to sound like a problem for the summer holiday!

I’ve discovered that a “27C256” and “AT89C2051” are actually the controller chips inside the keyboard

I may be very rusty, but 27C something is an EPROM. 256 divided by eight… a 32K EPROM. The other one will be an Atmel microcontroller, given the name I would hazard a guess at it being something based upon or compatible with the infamous 8051 microcontroller.

Just a guess while waiting for Dr Who to start. :-)

I may be very rusty, but 27C something is an EPROM. 256 divided by eight… a 32K EPROM.

Yup.

The other one will be an Atmel microcontroller

I believe so.

altering things is a case of knowing the code that needs putting into the EPROM – so a data sheet for the controller is required.

Dr. Who is on, no time to research the controller details.

Some useless details I just remembered: there were three types of “Acorn”/“Archimedes” style keyboards. The oldest (Archimedes – A3xx, A4xx) had an 8031 inside along with an (EP)ROM. The A3000/A5000 keyboards were based on the 8051, which did not need an external ROM chip, because the 8051 itself has the (masked) ROM storage inside (4 KB IIRC). The final keyboard (A4000) had an 8751 inside, which is an 8051 but stores the stuff inside an EPROM on chip.

I also remember that the initial keyboards had a bug in their ROM…

Another possible problem. I’m not sure if the wiring is like a PS/2’s. IIRC plugging a PS/2 keyboard into an Arc stops it from booting. Don’t know about the other way around.