I'd built the picocomputer and was seriously stoked to have output to a VGA monitor, but hadn't gotten as far as getting anything to run on it, and honestly I wasn't sure what the next steps would be. Now thanks to your help, I'm up and running. This is so cool. Thanks so very much!
I just ordered my second PCB from Rumble so I can build one for a friend. I'm lucky that he lives just a few miles away. The PCB is just like the ones we made in the mid 1980s, all green and through hole. Beautiful!
Actually I've already watched rumbledethumb video.. and was thinking of making it myself.. I'm glad that you have taken the windows route..and now I got 2 option to do it... thanks for making this video it is very helpful...❤
Thanks for leading the Windows Expeditionary Force. Now that we have something working in Windows, folks can start grinding away the sharp edges. Many hands make light work.
I enjoyed this video, even though I don’t know what I would do with the computer once I’d built it. That may not stop me, as I enjoy putting things together. I look forward to a followup video.
Great video to watch alongside Rumbledethumps' series. Having used Visual Studio for decades (professional Software Engineer), I'm somewhat averse to installing VS Code as well. It's a pity that Microsoft didn't make the two a bit more compatible with each other.
I think you could just use some resistors you already have. Resistors have all slightly different values, so finding the correct ones is possible. Those non-polarised capacitors are used only for audio, so regular polarised electrolytic caps would do as well.
Saw you there and I thought "Oh, my God, look at that interface You look like my next mistake...". Yeah, this looks like a great idea for me 😂 I'll build it, get it working, with all the intentions of using it to program with, then it will sit on the shelf for 6 years collecting dust! 😅
@@leesmithsworkshop I think it was a case of missing a key detail out on the way the values being converted from digital to analogue need multiple bits per channel, with the significance of the bits directly relating to the size of resistor applied to it before being combined to create the analogue output. It's what you clearly meant to say but I don't think it came out quite right, or at least it confused me and I know what you're trying to say. The resistor values for a linear DAC should halve from LSB to MSB - in the 5-bit DAC you have on the board the values are conceptually 500R, 1K, 2K, 4K and 8K but resistor values aren't quite that clean so you get 499R, 1K02, 2k05, 4k02, 8K06 (all at 1% tolerance, or better). No ones given me a clear answer on why not just 500R, 1K, 2K, 4K and 8K when they are all available... the answer will be in the maths... The need for high accuracy resistance values in the ladder are generally a problem because some values are nearly impossible to find. The R-2R approach is a lot easier as you only need two different resistor values and you can fudge it with just one but takes more explaining. That and the maths are a bit horrible to look at and you need twice as many resistors (2n+1 to be precise)
@@julianbrown1331 I agree I didn't explain the pico wiill have one digital output for each of the resistor values. What would happen if I made another with the closest values I do have would it be noticeably different on the screen ?
@@leesmithsworkshop It depends on how close - you can get some odd video artifacts. I use 1% tolerance components for the Dragon 32 board and actually test them to try and get them close because the DAC is used for audio input and output, and both joysticks (feeding the input and the DAC value through a comparator to estimate the sampled value - horrible, messy but it works), if you get it wrong the algorithm can settle on the wrong value which makes for some crazy behaviour With video you can generate grey/colour scales and see if it is smooth. Sudden jumps or retrogrades are generally quite obvious but at least you know where to look. For a linear result you want the values as close to doubling with each step but while that is great for audio it can result in a waste for video if you want a full spread of visible colours but for simplicity here I suspect it is just meant to be linear
Cool project! I can't help but think of the irony of using a couple 120 MHz dual-core Pico computers as helper devices for the venerable olde 6502. (Frankly I'd prefer something like this built into a C64 cartridge utilizing the 6510 -- THAT I would build.)
Picos essentially bridge nostalgic 8 bit world and modern sd card/fat fs/usb keyboard/vga conveniences. I feel it is not very different from retro machines with dedicated display processors, like msx. Except that pico is a lot cheaper and given the specs, display processor capabilities can be coded in esp32 software and not wired in custom hardware. It is still an 8 bit system in real hardware but you can "design" your own "yamaha v99xx" for it right in your vscode thanks to picos. Mine still looks like a bag of parts from mouser and a stack of 5 PCBs from pcbway but I am definitely planning on building it.
I can understand the desire to build from a kit. But for those that just want a modern 6502 computer, there's the neo6502. It uses an RP2040 (The newish Raspberry Pi microcontroller) rather than 2 Picos. And costs around £30 / $30 / 30 Euros as a built board.
