Picocomputer 6502

[kktos]

That's a project I'm following. Same for Paul's Neo6502.
I was initially wondering why using a RP2040 instead of (a lot of) logic chips...
Then I realised that is precisely what happened in the computer history. I mean, the builders are always trying to lower the costs.
I do remember the first sound cards I had on my PC. And the size of them. And the size of the last one I had.
So, all of a sudden, it hitted me: that's ok to use an integrated chip to do a lot of things I can do with a lot of chips.
So now, my brain can cope with it. Sorry, I'm a slow learner :)

I'm an old applemaniac (oh, by apple, I mean apple //, no mac) and how sad I was to see those PCs getting a lot of evolutions, new CPUs, new sound cards, new graphic cards when my poor IIgs stay as it was.
Since the end of the 80s, I'm dreaming about a possibility to do something similar for the apple //.
And boom, such a thing like the pico happened.
It makes me dream again.
That's good. Really good.

/kktos

[BigEd]

Yes, integration is wonderful! The VIAs and ACIAs were really quite complex back in the day - not to mention the floppy disk controllers. Oh, and the video chips.

[BruceRMcF]

BigEd wrote:

Yes, integration is wonderful! The VIAs and ACIAs were really quite complex back in the day - not to mention the floppy disk controllers. Oh, and the video chips.

Or the 6531 with GPIO and RAM on the same chip ... that thing was a RIOT.

[barnacle]

He's here all week folks!

[BigDumbDinosaur]

BruceRMcF wrote:

BigEd wrote:

Yes, integration is wonderful! The VIAs and ACIAs were really quite complex back in the day - not to mention the floppy disk controllers. Oh, and the video chips.

Or the 6531 with GPIO and RAM on the same chip ... that thing was a RIOT.

<Groan>

[okwatts]

I am about to build one (or two) of these. Let me explain as there have been some people who are perplexed by why you would do this. I have a SYM-1 and KIM-1 from about 1980. They were my first and favourites and the 6502 my best understood processor, in fact the only one I can really write in assembly language and understand. I have only ever been an avid hobbyist, never a programmer for employment (although I have written small programs in a number of languages as part of working as well as for hobby interests). After rediscovering the forum I have been avidly following and have built real hardware from Rich Cini and Plasmo primarily, I have simulated (emulated??) using Atmel (Daryl Rictor), (Oscar Vermuillen), STM (various), Raspberry Pi (Daryl Rictor) and FPGA (Grant Searle). I have been using Arduino,ESP32,Raspi RP2040 for hobby and as far as the 6502 is concerned the Pico-56 (Visrealm) is something along similar lines. That all says I am intrigued (obsessed?) with the 6502.
One of the reasons I am doing these projects apart from my own interest is that I have a grandson who is interested in computers and programming. I have passed on Raspberry Pi's , Arduinos and ESP32 to encourage him. I encouraged him to learn python (rather than Batch or shell programming), I have passed over Pico's programmed in MMBasic but he is more interested in C and C++ for his future. While the 6502 is good for understanding the basic concepts of computing it's not a fruitful place for him to spend much time. Hence the Picocomputer 6502. It's something that allows me to see another way of doing things, real hardware as well as Pi Pico's and while I may never really understand the C part of it, I will be stretched to setup the environment and will enjoy learning more. I am hoping that the C development (process and tools) and the use of the Pico's will tweak the interest and further the learning for my grandson. It might even make him curious about the origins of computing and the role of the 6502 in it.
I would rather spend my time remembering and recreating the past than learning AI,multiprocessing, and CUDA. It says more about my age and personality that instead of being forward looking and trying to at least understand the cutting edge I do what I do. However I don't want to hinder my grandson with my passions but only encourage him to develop his, given that he at least shares some of the same interests as me.
End of indulgent self-justification!

[fachat]

I've only now been looking into this.

What I wonder, and what did not become clear to me after watching a few of the videos, is what is running where?

For example I looked into fatfs video - it's totally unclear if that code is running on yhe 6502 or the pico.
Or the pixel bus. From where to where does it go?

Maybe there are some diagram how it all works, but I didn't see them.
Anyone has a pointer?

André


@

[sark02]

I just noticed this thread, and took a look at a couple of the videos. I think it's great! The Pi Pico is such a versatile little chip, and it looks like its finding its way into lots of different retro projects.

I think using the Pico/RP2040 like this, as a bus peripheral (as opposed to going full 6502 emulation), is a fine evolution of the tradition of building 6502 computers with custom hardware for video, audio, and I/O. The Apple 2 may have started with TTL for these things, but designers quickly moved onto custom chips, like the era machines from Atari and Commodore.

Today we can build era-like computers with a real 6502 attached to an FPGA... Taking on the role of both the system designer for the whole board, as well as the logic designer for the custom chips. Keeping somewhat within the constraints of the era... to whatever degree suits one personally.

The RP2040 provides a challenging, but more software-centric route into this world... Much simpler to integrate, hook up, and get working - especially in its Pi Pico module. An introduction to digital design... a half-step towards going full Verilog/FPGA.

I love it. Nice work!

[GlennSmith]

Hi all,
Today I looked at one video, and looked at the github stuff... My first reaction is 'Bravo' for the sheer quality and completeness of his offering - having hosted and developed on-line content myself I'm just gobsmacked at the time and effort he's invested.

Second reaction : erm some sort of 4-letter word? It's a little like the day when, having been "black belt" with Microchip PICs (in assembler, Basic and Pascal) for a few years - I discovered Arduino. It was a bombshell for me. Suddenly I could code in a decent high-level language(*) and have access to an unimaginable library of functions and APIs for just about any type of device. I could concentrate on the real heart of my know-how... And so many solutions I designed have either a bare ATMEL chip that was programmed with the Arduino IDE - or an actual Arduino Nano sitting on the board. Many happy customers, and a fairly easy job to provide after-sales service.

I might not use his SBC design, but I think I'm going to seriously look at his RIA and the API library for using CC65. He's got solutions for a proper user stack, a very neat sound card, and many other features that I've been striving to create on my own - where for the most part I really just want to get down to writing my 6502 applications in a nice language.

Another 4-letter word. His SBC is so simple and cheap, I think I'll just order the parts and get on with it. I can then design my own board with the extra VIAs and the few other bits I wanted.

(but, for the record, I *will* write-up if my user stack solution in SPLD actually works or not... (EDIT : once I get the board from PCBWAY))

(*) I have even written C++ dynamic memory structure algorithms that run in the few Kb of RAM in the little ATMEGA328P Uno. Arduino forum members said "it can't be done"...