6502 Hacking Hack Chat

Making 8-bits matter

Wednesday, April 3, 2024 12:00 pm PDT Local time zone:
Hack Chat
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Anders Nielsen will host the Hack Chat on Wednesday, April 3 at noon Pacific.

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Back in the early days of the personal computing revolution, you could have any chip you wanted, as long as it was 8-bits. We've come a long way since then, and while nobody seriously hopes for a wholesale return to the time when a Commodore 64 or Apple II was the home computing power play, there's still a lot to be said for the seat-of-the-pants feeling of the day. Our engineering forebears had their work cut out for them, and building the home PC revolution from the ground up with microprocessors that by today's standards were laughably limited is something worth celebrating.

Every retrocomputing enthusiast has their own favorite chip, and for Ander Nielsen, it's obviously the 6502 -- enough to give birth to his 65uino project, which put the storied microprocessor at the heart of an Arduino pin-compatible microcontroller. It's a neat project that seems to have caught a lot of people's imaginations and opened up a world of hardware and software hacks that modern hardware just doesn't need. Getting closer to the silicon is the goal of retrocomputing, and Anders is making it easy to get involved. And we're lucky enough to have him stop by the Hack Chat to talk all about teaching the 6502 some 21st-century tricks. Stop by and join in the discussion, and maybe you'll catch the 8-bit bug too.

  • Hack Chat Transcript, Page 1

    Tom Nardi04/03/2024 at 20:44 0 comments

    Anders Nielsen  3:00 PM
    Thanks Dan! Hello everyone! Super excited to answer any questions. Really been itching to jump in ahead of time By day, I'm the MacAdmin at Aalborg University, Denmark, handling about 1000 Macs. In my free time I like to play with old and new IC's and to get as much as possible out of as little as possible - most fun per transistor or most fun pr $ are favorites of mine. I've played with electronics since 2014.. or since early childhood if disassembling anything with a battery counts.. I made my first 6502 computer in 2021, followed it up with an entry for the 2022 Hackaday Prize, and was super happy the to see that go to the semifinals. Since then I've made the 65uino, which is a lot easier to manufacture and put together, but has it's own limitations - like the 8K address space and 128 bytes of RAM. Like an Atari 2600. And I almost have a PCB ready for a super super cheap (E(E))PROM programmer.
    Anders Nielsen  3:00 PM
    Oh - and I have a small Youtube channel where I try to explain most of the things I make, so it's easier for other people to replicate.
    Anders Nielsen  3:01 PM
    But ask away - I'm not an expert on any of it though.. Except my day job.
    Dan Maloney  3:02 PM
    Was the 6502 a nostalgia play for you? IOW, did the chip feature in any of the machines of your younger days?
    Anders Nielsen  3:03 PM
    Absolutely. When I was a kid in the 90s I had a C64 but I didn't have any of the knowledge to actually use it for anything but games.
    wheagy  3:03 PM
    Do you ultimately expect this to be a drop-in replacement in machines like the Apple II?
    Anders Nielsen  3:04 PM
    The Apple II should accept mostly any old NMOS 6502 I believe?
    Andy Geppert  3:06 PM
    The 65uino is awesome and very inspiring. Thanks for imagining and making it available! I think 65uino Mega is a good name for a future version which adds more memory, a full 6502 maybe some ADCs… ;) and a cartridge slot…
    Anders Nielsen  3:06 PM
    The waste stream I refer to is slightly abstract. Millions of Atari 2600's have already been recycled and I have a feeling there's still piles of boards in a container somewhere. If we buy those from the usual markets, we encourage the scrappers to save the chips instead of just melting them down.
    Anders Nielsen  3:06 PM
    @Andy Geppert Someone on Twit.. I mean X.. Suggested a 68Kuino :D
    Andy Geppert  3:07 PM
    Oh, and thanks for making the bootloader and dev work flow to go with it!
    Andy Geppert  3:07 PM
    Oh yes, 68Kuino needs to be done too!
    Dan Maloney  3:08 PM
    One vote for the 1802uino too. Probably the only one :-(
    Eric Hertz  3:08 PM
    What language do you most-use for 6502 programming?
    jdanen  3:09 PM
    @Eric Hertz - cool site, but there's an ocean in the way, shipping might get expensive :p @Anders Nielsen - ah, so basically picking the chips out by the invisible hand of the market, not a half bad idea
    Anders Nielsen  3:09 PM
    I try to explain most pieces of tech and code I use in my videos - but lemme tell you.. Editing video of 6502 assembly code and making it interesting is tough.
    Anders Nielsen  3:10 PM
    @Eric Hertz I'm slightly interested in that "phone" too :D
    Anders Nielsen  3:10 PM
    I mostly just go with 6502 assembly - cc65 does a decent job with C i head, but I haven't played with it much.
    Jacob Christ  3:11 PM
    It so easy to assemble by hand, why do you even use an assembler?
    Eric Hertz  3:12 PM
    LOL use toggle switches!
    Mitsuru Yamada  3:12 PM
    In my case, it is my homebrew floating point interpreter (7kB) or hand assembly.
    Anders Nielsen  3:12 PM
    @Jacob - almost getting there :) Actually want to build one like @Mitsuru's - but RAM only :D I have something to show you @Dan Maloney ...
    Read more »

  • Hack Chat Transcript, Page 2

    Tom Nardi04/03/2024 at 20:44 0 comments

    Anders Nielsen  3:42 PM
    Pot stirring time. The 65C02. I might sound like I have strong opinions about it sometimes... But.. I just feel it came around at a point where it was just "another micro".
    Anders Nielsen  3:43 PM
    Am I right the Rockwell C02's are pin compatible but the WDC's are not?
    Mitsuru Yamada  3:45 PM
    The 65C02 surprised me at the time with its low power consumption.
    J.B. Langston  3:45 PM
    yeah, the wdc is not pin compatible but can be made so with a few simple mods
    Anders Nielsen  3:45 PM
    For my "bigger" #ABN6502 SBC R1, I had to add jumpers for the WDC but I believe a lot of relabelled ones that turned out to be C02's actually works without the jumpering.
    J.B. Langston  3:46 PM
    i have put one in my apple IIe that came with an original 6502 and it worked, though i later purchased an enhancement kit from reactive micro which came with a rockwell 65c and the updated roms
    Xark  3:47 PM
    From my understanding PIN 1 is slightly different in WDC 65C02 (it is an input and output so needs a resistor or similar). 🤔
    Anders Nielsen  3:47 PM
    @Mitsuru Yamada I have a USB cable that changes color with current - I spot a lot of "fake" 6502's from the unexpected power usage. Could also be bad silicon of course. It's fun when a 65C02 is labelled MOS6502A in super clear paint.
    Pete Willard  3:48 PM
    I've not imagined that there would be a benefit to updating the 6502 in my IIC
    Anders Nielsen  3:48 PM
    @Xark Pin 1 is GND so a resistor won't do :)
    J.B. Langston  3:48 PM
    some later software only worked with enhanced IIe... i think the IIc already came with the cmos chip
    Xark  3:48 PM
    Okay, never mind me, but some info here:
    J.B. Langston  3:49 PM
    yeah you have to clip pin 1 off and tie bus enable high
    Anders Nielsen  3:49 PM
    Anders Nielsen  3:49 PM
    Good chart!
    Pete Willard  3:49 PM
    BTW JB, thanks for the TMS9918 board for the RC2014...
    J.B. Langston  3:50 PM
    oh, my reputation preceeds me ;)
    Mitsuru Yamada  3:50 PM
    Regarding the subtle differences between the 6502 and 65C02, in my experiments, when I replaced the 6502 and 65C02 on my own computer board, the number of clocks from reset to the first instruction execution seemed to be different.
    DrG  3:51 PM
    Did all those C varieties maintain the bugs in the 6502?
    Xark  3:51 PM
    Yes, clock timing is indeed different on 65c02. It has an extra cycle on some instructions, e.g.
    J.B. Langston  3:51 PM
    no the C got rid of all the undocumented instructions and replaced them with NOPs
    Pete Willard  3:51 PM
    Geez. I never knew that
    J.B. Langston  3:52 PM
    also added a few other instructions
    Anders Nielsen  3:52 PM
    Or "new and interesting" instructions. Like STX, STY,
    J.B. Langston  3:52 PM
    there's a load zero iirc now
    Anders Nielsen  3:52 PM
    I mean PHX
    Xark  3:52 PM
    Yes, fixed (most of) the bugs. In fact one of the extra cycles added was to correct JMP ($xxFF) bug.
    Xark  3:53 PM
    Several very welcome new opcodes and some semi-useful new addressing modes.
    Xark  3:54 PM
    Most useful IMHO are as mentioned PHY/PLY/PHX/PLX, but also INC and DEC of A is handy, along with BIT #$XX and the new ($XX) addressing mode can sometimes be handy to not need to load Y with 0.
    Anders Nielsen  3:56 PM
    I always find it interesting to check the ones I get. You'd be surprised.. Well you might not.. Some might be surprised to find how many 6502's "fail" the BRA test.
    Xark  3:56 PM
    Nice rundown of the improvements (and examples of use): ...
    Read more »

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Tony wrote 04/05/2024 at 02:06 point

it sounds to me that you are remembering the days chin up have fun play make things for your children instead of buying things for your children hopefully get them interested and let them help and boy does that make you happy I don't know but it makes me happy good luck

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Tony wrote 04/05/2024 at 02:05 point

it sounds to me as though you are remembering it and living it still perhaps that's why you wrote your comment good luck I hope you realize that you still remembering have fun young man have fun I fail at things but I don't care I have fun my children have fun with me so I'm happy I hope you are too

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nerill.dp wrote 03/27/2024 at 18:46 point

These and their counterparts set off the revolution that has become ubiquitous.

I remember the day when coding prowess was measured by writing the best program with the fewest keystrokes. I love the capabilities we have now and have no desire to return, but there great satisfaction in the minimal: getting the same output by using five fewer lines had you carried around the basement in your office chair - okay nevermind, that's how I WANT to remember it.

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