Hey all!

I've been quiet for a while but the Lattice iCE40 6502 project is still alive and growing. A few new things to report:

I've started a new GitHub repo which provides an 800x600 60Hz VGA output. Find it here:

https://github.com/emeb/up5k_vga

One of the side effects of the new video is ...

...I tackled the load/save issue in my implementation by LISTing to a text file, then importing text as if it had been typed. Slightly slower than a binary memory dump, but effective... ehBasic does have hooks for load/save though, but I've not used them.

That's exactly how I do it too, but I ...

Do you want MS Basic or is ehBasic (which is more or less MS Basic) good enough?

There are many ehBasics out there - the one I'm using has some 65C02 "updates" and is a single file in ca65 format. I can't take responsibility for the 65C02 tweaks though, that was our member: floobydust http://forum ...

I seem to recall someone had ca65-syntax source for MS 6502 BASIC in a single .s file somewhere, but searching only turns up the mist64 implementation that's spread out over many smaller files. Anyone have a link for the single-file version? I've seen Grant Searle's version too, but I thought there ...

Thanks for the Mandelbrot code. I modified it to generate a 100x75 16-color version on my FPGA-based 6502 system

Added a new feature to the PS/2 keyboard port: host to device communication is now supported which allows the caps lock LED on the keyboard to indicate the previously hidden internal caps lock state of the PS/2 keymap to ASCII decoder. Not a huge step forward, but it was a bit of a challenge and fun ...

My go-to PCB fab is OSHpark - they're super inexpensive for the tiny boards which I tend to do often and their shipping is basically free, but there's a breakpoint around $25-30 where they're not the best choice. I've used JLCPCB several times for some fairly simple (but larger) 2L designs that ...

Some new updates to the 6502 project:

* Expanded the BASIC LOAD & SAVE commands to use SPI flash
* Modified video RAM access as dmsc described above - RAM is clocked at 2x the CPU frequency and access is interleaved between video and CPU to simplify arbitration.
* Added NTSC color generation with a ...

One of the annoying things about the OSI version of 6502 MS BASIC is that the backspace function used the underline character. I've studied the MS source and made a fairly simple patch to allow it to use the actual backspace (Control-H) character. Since I load the code from flash at boot time and ...

My MS BASIC interfaces are up on the github repo now:

https://github.com/emeb/up5k_basic/blob ... 65/basic.s

This includes the modified LIST function, as well as the LOAD/SAVE routines which interface to SPI Flash.

ROFL - of course it has. Nice of them to put it up on github too.

Interesting thing is that this appears to have been converted many years before the M6502.MAC source file was widely available and a lot of the labels etc are different. That suggests someone did this by reverse engineering the ROMs ...

I've not tried what you're doing, but be content in the knowledge that what you're doing has already been done, tried and tested and used for a long time by ... Apple. So you're doing the right/best thing by all accounts...

OK, thanks for the insight - nice to know I'm not totally out to lunch ...

I'm building a home-brew system based on the OSI Superboard II that I started with long ago (HW details in this thread: http://forum.6502.org/viewtopic.php?f=10&t=5559 ) and one of the things I'd like to improve is the process of saving and loading programs. The original OSI approach was that SAVE ...

Latest updates:

* Removed 8kB BASIC ROM.
* added 20kB RAM in range 8000-CFFF
* added write protect option to RAM on 4kB boundaries
* Boot ROM now loads 8kB BASIC from SPI flash into protected RAM at address range A000-BFFF
* added 4-voice sound generator with 0-32kHz range, choice of waveform (saw ...

Comparing with my own project at https://github.com/dmsc/my6502 , you implemented a few thinks differently:
Yes - I started with a system architecture that was based strongly on the old OSI Superboard.
- You have the video RAM separated from CPU RAM and access through the video module, I have ...