[Oberon] Project Oberon on Arty A7

[Chris Burrows]

> -----Original Message-----
> From: Skulski, Wojciech [mailto:skulski at pas.rochester.edu]
> Sent: Thursday, 10 December 2020 5:24 AM
> To: chris at cfbsoftware.com; ETH Oberon and related systems
> Subject: RE: [EXT] Re: [Oberon] Project Oberon on Arty A7
> 
> Chris:
> 
> > Note that Cmod A7 has such a chip on board. So you can look at
> developing the memory controller for it using Cmod A7. It is still
> ASRAM, which you need to access four times to deal with 32 bits.
> 
> After I sent this e-mail, it occurred to me that after you managed to
> run the full Oberon in 0.5 MB, the Cmod A7 has exactly that much. It
> is the only Cmod with extra memory. This memory is 8-bit wide, what
> limits the BW, so competition for video would be heavy, unless the
> video buffer is in BRAM.
> 
> Cmod A7 is not sharing the GPIO pins with its single PMOD. It is a
> really nice board. I am looking at it for my own projects with using
> Astrobe. These ideas are evolving, though very slowly. The 0.5MB is a
> very attractive option for my projects to hold data tables. Like I
> said, it is the only Cmod with that much memory.
> 
> Wojtek

If that is what you want then just do it! It would be a nice student-type
exercise to gain experience with modifying the system. Embedded Project
Oberon is supported on the CMod A7. If you want to adapt the Verilog sources
to use the SRAM and are happy with it running at a lower clock speed (12.5
MHz?) you should just need to modify our Verilog code and use the compatible
disk image. You can download both on request:

https://www.astrobe.com/RISC5

I would have thought that shouldn't take too long to get going if you also
look at the official Project Oberon Verilog sources and can work out how to
handle the difference between 8-bit and 32-bit memory accesses.

I wouldn't consider the CMod A7 as a suitable platform for the Project
Oberon Workstation myself but I'm happy for you to prove me wrong,

Regards,
Chris Burrows
CFB Software
https://www.astrobe.com/RISC5