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Kevin Williams

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Kevin Williams last won the day on July 25

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  1. Hello Everyone! I received the parts for the third Prototype on Tuesday evening and spent a good chunk of that night and a bit of yesterday morning getting it worked out. I had to get my code moved over to the ATTiny861 before the board would even power on. This turned out to be pretty easy now that the I2C header will also work as an Atmel ISP programming header. Of course, I'm pretty much going to make a mistake somewhere on a board of this size, and this time is no exception! Fortunately, they were easy to spot and the actual logic is working as it should. Or at least as I designed it. Two of my mistakes are visible in the pic, see if you can find them. One is just cosmetic, and the other is a bodge job on a chip which I will admit, is next to impossible to see in this photo. The less easy to spot issue is that I used the stand-by power to power the microcontroller, but I put pull-up resistors on the I2C lines (and SPI programming lines) to the system voltage and not the VSB. I did this on purpose as I didn't want to pull these lines high while programming the microcontroller, but need to pull them high for I2C. The net result is that leakage was happening backwards through these resistors when the data/clock lines were high. Enough to power on the LED on the motherboard with no other ICs plugged in. Took me a minute to figure that one out, but I think I will just throw a few more diodes in to protect this from happening. I suspect issues like this are sometimes why you may see a lone crusty resistor on an old PCB after years of use. Easy fixes all around! One last issue is that the parts sourcing scourge which has been affecting the world is also affecting TexElec! Yes, we can't get parts in for some of our products, and as time goes on, it seems like it may get worse before it gets better. And now, it has hit the X16 project! I am unable to get the FPGA and the DAC for the new Version 4 VERA, so we're still running V3. The main difference has to do with hardware deadlocks on the SD card, so functionally, it's fine. However, the lead times are a bit concerning. I'm looking into some other suppliers now, and hoping for the best. For now, here's a pic of the new machine, with no wires all over it! Take care! -Kevin
  2. While this is true, the reality is it's not working correctly. I'm not 100% sure why, but the VERA is not initializing correctly with the current kernal. Michael Steil is not a fan of the 816, so I'm guessing it won't be high on his priority list.
  3. The bus pins may be a little misleading as some of them have the 65C816 names labeled. I am debating on exactly how to label the board, or whether or not I should at all. Even though the system is designed to be a 65C02 based machine, I designed it such that a 65C816 will work electrically in the board. The Kernal isn't a fan of the 816, so it would have to be running a different OS, but we wanted to make sure people had the option to do what they wanted with the system. When I moved to the 60 pin slot, I had enough room to move nearly all of the CPU lines over. So long story short, I should probably label the board based on the 02 names, but I've been focused on making sure you can still plug in a 816 with no HW mods needed other than swapping the chip, and the code of course. The Audio lines are inputs which are sent to the audio mixer, left & right channel. I know it's unlikely there will be a need for more sound chips with the VERA and the YM2151, but I thought someone might want to add a SID, or maybe put the SAA1099 back on later, etc. It will just allow you to pump audio in from an expansion card. I moved the pins to line up with the actual layout of the CPU to simplify routing. It's the beauty of nothing being carved in-stone.... Yet.
  4. Hey Everyone, Sorry for the delay on an update. It's been a hectic year once again and there never seem to be enough hours in the day. I'm not a huge FB fan either, but the reality is with our business, it's pretty key I keep on top of FB & the even more dreaded Twitter. I meant to post the same day, but for the brief second I tried, the site wouldn't let me login, and I just forgot to come back. However, I just posted a video of Attack of the Petscii robots on the X16. It's still the second proto, but I have it wired as the third board is designed. I did this for testing the new design before running it of-course, and David just wanted to make sure the game was still running ok. I am catching up on the thread and I will answer some questions here in a second. For the moment, the PCBs are 100% complete and should be shipping tomorrow. This means probably Friday or Monday they will be here and I should have all of the parts in-hand too. We're still not done with the Kernal, so this is not the end of the story by any stretch, but it should be pretty close to the end of the HW specs. Attack of the PETSCII Robots on the Commander X16 Prototype 3 - YouTube Thanks, -Kevin
  5. Hey Everyone, I just made a new video showing some updates on the Commander X16 second Prototype. I've been working on a few modifications, and getting them incorporated into a daughter-board. The board was updated, and sent over to Michael Steil to work on the kernal. At this point, he should have what will be pretty close to the final HW. I cover a few topics, so please take a look if you have a second and thanks for taking the time. Take care, -Kevin https://youtu.be/T5vjnBYGp2w
  6. It will cost more, but the vision of the first step is through-hole and easy to understand. Later versions will be surface mount and cost reduced.
  7. Hi Everyone, If you happened to see David's video on the Color Maximite 2, then you probably noticed that the new Commander X16 PCBs have arrived! David @The 8-Bit Guy just happened to swing by my house the day they arrived, and he picked them up before I was even able to get all of the parts in. I am still waiting on a few things, so I haven't been able to complete assembly yet. The VERA is also not complete for this reason, but I had to mock it up for the pics! Bear in mind, this is not the correct case, this is from an old tower ATX case I had sitting around. It's a nice platform to mount the board and make sure I have the placement of screws, slots & of course the rear ATX panel aligned correctly. I will likely make a few placement tweaks but overall I am quite happy with the physical layout so I just had to post some photos! So far, it's working but my ATX soft-start circuit is a bit squirrelly. Not only that, I kinda wired it wrong and didn't catch it before the run. Worked great on the breadboard, but I will have to revamp that before the final. There are also a few other little things discovered since this proto was run, but the real tests will be coming when @Michael Steil is able to get the Kernal up and running. (I would write some test code, but one part I'm missing is the ZIF socket for the ROM. Should be here in a day or two.) @Perifractic is also sending me the X16 case, so I should be able to install the board in there later this week. Happy Sunday, and Take Care Everyone! -Kevin Williams https://TexElec.com
  8. Hi again! I've been working for quite awhile to get the new layout complete, and I think we are just about ready to run the second prototype! There are quite a number of changes to this board over the previous version, so I do expect a few, ahem, challenges perhaps? That said, a lot of time has been spent testing on breadboards and optimizing so I think we should be close to the final specs on this system. As mentioned, there are code breaking changes with the system. I will post more for the devs out there in a post below. The VERA has also changed quite a bit. Namely, it now has 32 registers, but I'll let @Frank van den Hoef talk more about that when he is ready to post some updates. Also, I made two proto boards to test the bus and get the alignment right for the final design. Progress is being made, thanks for everyone's patience and have a great day!
  9. Hello Everyone! I know it's been awhile since there has been an update, so here goes: Earlier this year I had mostly completed the "Proto #2" motherboard. It was a mad dash to get the PCB made before we met in New Jersey at VCF. Right at the end, @Frank van den Hoef made a pretty substantial change to the VERA, which required a bit of reworking. April came, the trip was cancelled and life went sideways for a bit for the world. As such, I decided I needed to focus on a few things for TexElec, and took a bit of time off from the project. Last month I picked up where I left off and planned to make minor changes for the VERA and get the PCB made. However, the team had some time to think and oversights and optimizations became apparent. One change led to another, and let's just say, we're gonna break some code. Sorry. I do believe the changes made will not disappoint. I'm not going to reveal them just yet. I am still laying out the PCB and would like to do some testing to make sure it's going to work as designed. I am trying not to release too much of the schematic until the end, as anything is subject to change at this point. The pic below is how I have the expansion bus pinned out. I may well move some the pins around to simplify layout, so again, not in stone yet, but I do think this is pretty close to what pins will be present. This post is majorly TLDR already, so I'll add a comment below with more info on the pins, and the idea behind some of it. Take care!
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