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PostPosted: Sun Sep 29, 2013 1:44 pm 
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jac_goudsmit wrote:
carmel_andrews wrote:
Interesting that you say that (i.e. that there's v. little interest in this site by Atari/Commodore users) since i would have thought that along with Apple as well as Atari and 8/16bit Nintendo desktop game systems, that in itself forms the majority of the 6502 user base and therefore the target market/audience for this site (unless I am clearly missing something, which i probably actually am)


I think what Whartung was saying (and I agree) is that many vintage computer enthusiasts come to this place to discuss the lowest level: how the 6502 works internally, how to build your own computer using the information from Garth's webpages, meet others who have already done such a thing etc.

I bet most people on this forum have worked with Commodores, Apples, Ataris and Nintendos at some point in time, but at 6502.org, I get the feeling that all the differences between those systems (differences between specific hardware and differences in opinion about how good or bad they were) are tossed aside. This website is about the 6502 and related CPUs, and most of the time we don't get distracted by the non-important stuff.

While there has been much discussion in this thread that I've enjoyed following and contributing to, I'm sensing that everyone still agrees on the basic issue: We would like to provide 6502 newbies with something that they can use to build their own 6502-based system, that preferably has a real processor, can do something useful, is not too expensive and should consist of components that are available at websites such as Digikey, Jameco or Mouser.

Some newbies may want to try emulators first, but they probably end up here when they're ready to build some hardware, or use some pre-built hardware that's not a vintage system from eBay. In the last 2.5 years that I've been working on my project, I've been getting enough attention that it makes me feel that there are a lot of people who would be interested in learning (or teaching!) about basic CPU technology that manifests itself in the 6502. And because my project does the bitbanging of the 6502 pins from a Propeller, it goes one step further and potentially gives students a look at what happens at the pin/cycle/datasheet level -- if they're interested.

I remember when I was 15 or so years old, I figured it wouldn't be too hard to build my own computer. I read about self-build projects like the Elektor Junior but it was simply too expensive and I couldn't think of a use for a computer so I never had one or built one. But I remember how much those books and articles made my hands itch to make something myself, even if it was just to show it off to my parents, family and friends. If it would have been possible back then to build a $50 computer kit that would have started out with no code at all but I could make it do whatever I wanted it to do, I might have gotten one just for the heck of it.

Maybe not all newbies will eventually buy a project (in kit form or ready-made); maybe some of them will buy a kit but will never build it. But for me, designing a kit and dealing with some of the technical aspects, sales aspects, and social aspects has been very educational, and I'm not even done yet. What matters is that eventually, we can pass on the sense of accomplishment that one gets when one builds their own computer from components, and makes it work. When I showed my grandkids that I have a Commodore 4032 now, they didn't even shrug, let alone make me pull it out and power it up to see how it worked. But I know they like soldering and tinkering and they enjoyed their visit to the Computer History Museum last year. And I'm pretty sure that, by letting them put one of my kits together, I can make them understand how I felt when I typed my first Basic program on a 4032 in school in when I was 12 or 13.

===Jac







I used to have a 6502 book featuring the Elektor junior computer as a target development system....I think i offloaded it to CEX (back in the days when they had a retro sales department)

I do still have some 6502 books (the better known ones from wiley, SAMs and sybex) as well as computer specific 6502 books for the A8, c64 and apple as pdf's and proper print versions

the wiley one though as been written in (I didn't do it, I bought it second hand/used from a popular atari/commodore h/w and s/w shop on the south coast (near brighton))


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PostPosted: Sat Oct 05, 2013 12:11 am 
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LOL: Lego, Arduino. You don't learn much from a prebuilt microcontroller using Python or C. I'm tired of people in my school calling themselves "hackers" because they know how to use command prompts and Linux. That's more noobish than me. Also since I have been with vintage computing, I noticed companies that used to make processors and computers making crap

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PostPosted: Sat Oct 05, 2013 12:49 am 
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James_Parsons wrote:
LOL: Lego, Arduino. You don't learn much from a prebuilt microcontroller using Python or C. I'm tired of people in my school calling themselves "hackers" because they know how to use command prompts and Linux. That's more noobish than me. Also since I have been with vintage computing, I noticed companies that used to make processors and computers making crap

The higher level stuff has its purpose in life. Try as you might, you can't build everything from scratch. Even if you had that capability and all the necessary resources, you wouldn't live long enough to see any results. There's just too much that has to be done to get from start to finish.

That said, as the level goes up the opportunity for learning tends to go down. Since you mentioned Linux, BASH is a good example, in that it carefully insulates the user from the uncouthness of the kernel API (which if you look at the assembly language used to call a kernel function, especially on x86 hardware, is not pretty). With BASH, you don't need to know the details of what's going on, for example, when you search a file for a text pattern using grep, sort the results with sort and dump them to a printer with lp, connecting everything with pipes. Or, the user may well know to type ps -ef | sort -nk 4 | tee /tmp/ps_out | lp -d hp4240a -o nobanner to see which process is hogging the MPU, but may not have a clue how or where ps got its data, or how tee is able to tap into the pipeline. For most users, what happens when the data stream reaches lp is a total mystery. Paper magically spews from the printer with the output of ps on it, sorted by MPU usage per process.

This is why folks like Garth and me try to encourage working as close to the bare metal as you can. The only way to see what's going on under the hood is by opening it and getting your hands metaphorically dirty. That isn't possible if an Arduino or Raspberry PI is the thing running your "homebrew computer," since the "hood" is bolted shut. On the other hand, if you scratch-build using an MPU, RAM, ROM, glue logic, etc., you will develop a good understanding of what is going on under the hood, because you built the automobile (to belabor the analogy).

There is a place for microcontrollers. If the goal is to build functional hardware as quickly as possible, the Arduinos and PIs of the world are a good choice, since much of the nuts and bolts engineering is already done. If the goal is to learn, however, they are not a good choice, especially true with the PI. A desktop machine running Linux is a far better environment in which to learn to use Linux.

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PostPosted: Sat Oct 05, 2013 1:01 am 
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Quote:
Try as you might, you can't build everything from scratch.

When I was in junior high, I had visions of making even my own transistors. I hadn't heard of ICs yet. As Ed put it so well, there are plenty of stopping off points between that and the top-level systems stuff. One of our sons is way up there in the systems stuff, working for an IT company, but doesn't even know what a NAND gate is. I'm at a much lower level than he is, and don't wish to get into his world.

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PostPosted: Sat Oct 05, 2013 1:15 am 
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GARTHWILSON wrote:
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Try as you might, you can't build everything from scratch.

When I was in junior high, I had visions of making even my own transistors. I hadn't heard of ICs yet. As Ed put it so well, there are plenty of stopping off points between that and the top-level systems stuff. One of our sons is way up there in the systems stuff, working for an IT company, but doesn't even know what a NAND gate is. I'm at a much lower level than he is, and don't wish to get into his world.

I frequently have to work at both levels, since I do hardware as well as software. That said, no one works to the component level anymore with modern hardware. If it doesn't work right or at all, you replace it. Not a lot of skill required there. In the past, I did some chip-level repairs but that was long ago. Back when TIA-232 was more commonly used, I'd occasionally replace failed 1488/1489 line drivers on-site while the customer watched. They thought I was a genius when the equipment started to function after the repair. The only real skill brought to bear, other than knowing which chip to replace, was being able to solder. :lol:

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PostPosted: Sat Oct 05, 2013 1:23 am 
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Design and repair are two different things though. Replacement substitutes for repair nowadays. Nothing substitutes for design. Even with CPLDs & FPGAs, someone has to design the innards.

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PostPosted: Sat Oct 05, 2013 6:48 am 
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James_Parsons wrote:
LOL: Lego, Arduino. You don't learn much from a prebuilt microcontroller using Python or C.

You can learn just as much, but in a different topic. For example, you could use a microcontroller and C to learn more about file systems. And because you don't have to worry about as much low level details, you can spend more time and focus on the actual file system design, and get a deeper understanding of it.


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PostPosted: Sat Oct 05, 2013 7:07 am 
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BigDumbDinosaur wrote:
This is why folks like Garth and me try to encourage working as close to the bare metal as you can. The only way to see what's going on under the hood is by opening it and getting your hands metaphorically dirty. That isn't possible if an Arduino or Raspberry PI is the thing running your "homebrew computer," since the "hood" is bolted shut.

Not quite true, though. Especially the Arduino is a very open design, and its heart is just an Atmel AVR controller with full documentation on each nut and bolt. If you wanted, you could throw away all the special Arduino tools and libraries, and get your hands quite dirty programming assembly language for it. The only real difference is that you can't touch the internal bus, but apart from that, learning to use the internal peripherals is just the same as using external peripherals.

And if anybody thinks there's not much to learn with an AVR, I challenge you to duplicate this: http://www.linusakesson.net/scene/craft/ (note: runs on 8 bit CPU, uses only 1kB of RAM, and 8.5 kB of Flash memory, and has no video or sound hardware).


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PostPosted: Sat Oct 05, 2013 7:41 am 
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Arlet wrote:
... And if anybody thinks there's not much to learn with an AVR, I challenge you to duplicate this:
http://www.linusakesson.net/scene/craft/ (note: runs on 8 bit CPU, uses only 1kB of RAM, and 8.5 kB
of Flash memory, and has no video or sound hardware).


I echo this comment from his page:

Quote:
I am amazed and impressed. Bit-banging VGA and using the SPI port as a video shifter is too clever...
wow. Does Atmel know about this demo of yours?


Waaaay out of my league !!! :shock:

Mike


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PostPosted: Sat Oct 05, 2013 8:55 am 
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not color, but something similar with the 6522's shift register to get raster graphics on an analog oscilloscope: viewtopic.php?p=15348#p15348

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PostPosted: Sat Oct 05, 2013 2:58 pm 
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GARTHWILSON wrote:
not color, but something similar with the 6522's shift register to get raster graphics on an analog oscilloscope:
viewtopic.php?t=1881&start=3


Yeah, I saw that Garth. Nice! A decent raster display sure seems to make a design "come-to-life", more than
LEDs or even a fast serial connection, IMO. This kid's project reminded of the Atari 2600 ... he has basically
applied the same ideas (with a ton of self-written software) and made the 21st century version ... the only
things missing are a joystick and cartridge port!

Mike

P.S. The bouncing banner in the demo appears to list a 'team' of programmers: I'm sure that they all have
cycle count dreams ... and nightmares!


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PostPosted: Sat Nov 08, 2014 12:03 am 
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nyef wrote:
To go along with this, some sort of sdcard-based disk drive emulator might be a decent peripheral, as new five-and-a-quarter disks might not be easy to find these days.

http://www.athana.com/html/diskette.html
You can even get them in 8"! :D

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PostPosted: Sat Nov 08, 2014 7:41 pm 
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When I crank up my Apple ][ (which I haven't in a year, sadly), I still have a tingling feeling in my belly. I wish I could share that feeling of the sky being the limit with the younger generations. I've been trying to figure out exactly what it is that makes me feel that way. An Apple emulator does not make me feel the same way - in fact anything that requires a modern PC seems to literally give me a headache.

Turning on the power switch and having a self-contained system come to life in seconds is a true joy. A KIM-1 does it, an Arduino, not so much. Working with Forth-based SBCs is almost pleasant, although the AVR harvard-based architecture has always made me cringe. Cranking up the Arduino compiler and compiling so called 'sketches' makes me feel like I should be paid for it.

I think it has to do with the total scope of the system. I can write or at least understand the _entire_ monitor or design a 6502-based board (maybe with some help from Garth). I can't (and certainly would not want to) write a C++ compiler and an IDE for a limited controller.

Well, I won't pretend that I can fully understand the C64 kernal, but I can probably get it to do what I want, and I can be certain that an 'update' will not render my work or understanding totally useless. Maybe my attraction to these obsolete devices comes from knowing that there will be no updates.

The world has gotten very big, and our modern computer systems are a reflection. Individual expression is actively suppressed by these enormous systems; at most we are expected to make a small contribution to a large project. The 6502 at its inception was a way for an individual to have a real computer system that they can fully control. It still is, although the parameters have changed. The freedom that the 6502 symbolizes today is not in the financial or performance domain. It is a freedom from overly complicated, constantly updating systems that shove advertising, DRM and 'intellectual proprty' down our throats.

So here we are, a year later... And today I feel even more then before that being self-contained, and understandable (at least not orders of magnitude out of range of understanding) and stand-alone (and completely under my control), are the key requirements for that special 'sky is the limit' feeling that I sorely miss in my life... And the thought that whole ganerations of kids may never experience it makes me sad.

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PostPosted: Sat Nov 08, 2014 8:55 pm 
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Well said, enso! Where's the "Like" button?" I think I'll bookmark your post as a significant philosophy observation!

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PostPosted: Sat Nov 08, 2014 9:15 pm 
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enso wrote:
When I crank up my Apple ][ (which I haven't in a year, sadly), I still have a tingling feeling in my belly.

Good post. I too would hit the "Like" button if there were one.

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