6502.org

You just read my mind. I was hesitant to do that, because there could be unintended consequences of making ROM into RAM. But, If I tucked a little xmodem-based program (for the sake of ease) somewhere in the address range outside of the current "ROM" address range, I could call it from the monitor and then use it to overwrite the monitor.

What do you think?

Jon

Oh, PS: I got that Pynq Z2 board you showed me a while ago. Amazing piece of hardware! It kicks the butt of the Arty Z7.

That should work, give it a try... Yes, I haven't done that much with mine, because I really hate Vivado. I did do a port of the Beeb FPGA last June, which uses HDMI and allows a USB keyboard to be used. It's still sitting on the dev branch. This is the top level design.

Dave

Speaking of the Beeb, I just watched Micro Men for the first time. I had no idea all that went on on your side of the pond - very interesting stuff! I hear Sinclair just passed away recently.

Dave, it worked!!! Now, if you want to replace the monitor ($C000-$FFFF), there is a small bit of hard-coded ROM at $B000. If you run it (B000R at the built-in monitor), it will start an Xmodem transaction that will allow you to upload a .prg file to replace the current monitor - all without re-synthesizing and re-implementing the whole thing!

Jonathan

Now I just need to re-write the monitor to take total advantage of the 65c816 native mode - I couldn't find any pre-existing 65xx monitors that weren't written for the 'c02.

You might investigate BDD's SuperMon 816 here: http://sbc.bcstechnology.net/
click on Downloads on left.

When I moved from 65C02 to my '816 boards I more or less kept the same C02 code and took the view that it was then up to the application to switch to native mode if it needed to. That made it easier to run up things like BBC Basic and so on.

-Gordon

That's what I'm using now, but the issue is that you can't access addresses beyond the first 64k (with, say, a traditional WozMon).

The other thing I'd like to try - but I don't know where to start - is going beyond just simple text over UART to some sort of primitive graphics. I still want to take input over serial, but I want to learn how to do VGA and character ROMs and maybe output to a VGA monitor.

Jon

I like what you wrote on your site about the question of obsolescence. Heck no!

Jon

Forum member Samuel Falvo (kc5tja) has a couple of good related essays:

• Neo-Retro Computing (If that ever goes down, it's also cached on my site, with his permission.)
• Software Survivalism (If that ever goes down, it's also cached on my site, with his permission.)