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!
THANK YOU Kevin for the update! Even when there's not much to say, updates are a heartbeat, you know?
And then there's these BIG updates which are just plain interesting, and as ZeroByte said, exciting even.
The hardware shortage "only getting worse" sounds ominous... but I suppose that ought to simply be taken and used as an opportunity to examine the system as it is and think about it.
Awesome! Kevin, I'd say not to hesitate to lean on the community too: If you have a particular list of things you need (FPGA etc) to get proto stuff done, post a list and let folks see what they've got (or can leverage connections to get). Obviously it won't be the endgame supply chain, but if you need something (e.g., to get VERA4 onboard and rocking) it could be the hive mind might be in a position to help.
As for myself, er... well, I've got a big bag of blue LEDs somewhere around here. ?
In all seriousness, thanks to you and everyone on the team for plowing through all the things with COVID, the global supply chain weirdness and the online bikeshed factory to get things so this far. Can't wait for the next steps!
Wow. I get more excited every time I see one of Kevin’s posts.
The parts availability thing has me worried, though. I know it will only be a matter of time before suppliers catch up on the FPGA and other parts that are in short supply, but it’s frustrating to see this happening right now and being unable to do anything about it. (Of course, I can’t buy an NVidia RTX 3080 for love or money, either, so….)
Wow. I get more excited every time I see one of Kevin’s posts.
The parts availability thing has me worried, though. I know it will only be a matter of time before suppliers catch up on the FPGA and other parts that are in short supply, but it’s frustrating to see this happening right now and being unable to do anything about it. (Of course, I can’t buy an NVidia RTX 3080 for love or money, either, so….)
I work for a government contractor. I'm a software guy, but we do plenty of specialized hardware in relatively low volume. Just chiming in with "hardware shortages in the supply chain are real" ... I think I can safely say that much without getting in trouble.
Is the specification of the V4 VERA the same as before?
Yeah. The only apparent reason for a different FPGA for VERA is for more RAM cache in the fabric for more VIDEO RAM and more colors in high resolution modes, and possibly scrolling registers on the bitmap.
The only apparent reason for a different FPGA for VERA is for more RAM cache in the fabric for more VIDEO RAM and more colors in high resolution modes, and possibly scrolling registers on the bitmap.
... or pricing concerns, or electronic concerns with how it works on the PCB, or with the clock, or one of a dozen other things. I'm sure it's not because they're going to crank it up to being a Neo Geo.
