gfoot wrote:
Nicely done, it looks like it's working really well!
It's interesting that you have two different colour depths supported, I'd be interested to hear how you did that. The BBC Micro did it in quite a clever way, arranging this so that it just had to shift the output shift register at a different rate and everything else was handled by software.
Interesting stuff about the BBC, I didn't know that, but it makes sense. That's neat! And same with you, I couldn't find any parallel in/out shift registers, it's tough sometimes.
Because the CPLD is grabbing the RAM color data on PHI2-low, and it itself is outputting the RGBI colors directly from the CPLD, all I did was tell the CPLD to alter those colors to whatever configuration I want. It really is always in 512x240x4 mode, but I just say "go slower when shifting out the colors" to make it look like 256x240x16 mode.
Paganini wrote:
Your surface mount soldering deserves its own separate wow!
Yep, "Wow, it's bad", right? Gosh, those SMD resistors and capacitors were not made with hand soldering in mind
And I either had the iron too hot or cold or something, or applied too much solder, because it would bead up and stay super round and often I didn't think it was actually attached to the pad properly.
For that CPLD, I posted it about it here:
viewtopic.php?f=1&t=7629&start=30#p101886The SOIC parts are super easy, but I get bridges all over the place. I just crank up the iron and use solderwick liberally, makes it looks much better! What was upsetting to me this time was that the SOIC-20W pads on KiCad did not match up to my 74HCT574! I mean, those pads were WIDE, and the chip just *barely* managed to touch both sides at once. Ugh. I thought I had measured from the datasheet! Oh well, it worked, but when I make another batch of boards I won't be making that mistake again.
plasmo wrote:
Great job! CPLD opens many doors.
Thank you, and yes it does. One "bad" thing I have noticed though is that I'm lazy with my logic because I know I can fix it in software later. One stupid thing I did with my CPLD code was have the RAM and ROM both active at the same time. Duh!
plasmo wrote:
Considering how expensive 65C22 is, you may consider eliminating it and replace with CPLD.
True. I actually haven't used the 6522 on the Acolyte boards for a while, so this was actually different for me.
plasmo wrote:
You can probably double, triple, or quadruple 65c02 clock now you have CPLD.
One day at a time, haha
Thank y'all for the replies
Chad