Thanks! I have many fond memories of serials terminals. I was a kid during the CP/M era in the early 80s, and was a college student at the tail end of the time-sharing era in the early 90s, so I have many fond memories of using serial terminals. Good times :-)
Another nice video. Thank you Dave. May I ask what baud rates you can support using the 3.6864-MHz crystal and 85C54 Timer, please? Also, are you using /16 for the baud rate clock on the 63B50 ACIA? TIA...
Sure! The way it's set up is that the CPU's E signal is fed to the 82C54 timer/counter, meaning that the 82C54 sees 1/4 of the crystal frequency, so 921.6 KHz. The 82C54 can do arbitrary integer divisions of that frequency. Dividing by 6 yields 153.6 KHz, and using the /16 mode of the 63B50 ACIA then yields 9600 bps. (Using the /1 divisor on the ACIA doesn't work, not sure why exactly.) 19.2 Kbps should be possible using a /3 divisor on the 82C54. Going with the /64 divisor on the ACIA, we should be able to get 57.6 Kbps, 28.8 Kbps, and 14.4 Kbps by using /1, /2, and /4 divisors on the 82C54 (respectively.)
Found what may be an issue with the Mem/Peri PCB vers 18 Aug 2021 I would like to preface this with.... FANTASTIC JOB.... So I am not being critical, just helping out if I can. So I have had all the boards manufactured, built up all my F68... But found some issues with the memory/peripheral board. It may be I have a newer Kicad, but you can check and see if you are seeing the same issues. U303 (6850) Pins 10 and 12 are supposed to be connected to Vcc and they are not connected to anything on my board. U301 Pin 4 (PA0) is not connected to J305. The via is there, but kicad seems to think it connected at another point. Again, this may just be a Kicad thing. I am still waiting for my Keyboard, but everything else is working.... Started building up Sound/Video card, too early to tell on that. Keep up the great work.
It's definitely on my agenda. I've thought about it a bit, and I have a general approach in mind, but I'm still pretty new to FPGAs, so there will be some learning involved.
![ทุกครั้งที่หลับตา (Lucid Dream) - AYLA's [ Official MV ]](http://i.ytimg.com/vi/4i1OBAQyv58/mqdefault.jpg)
Nice. Well done. Glad I'm not the only one who's surprised when stuff works first try. :D
I know, right?
I missed being in college so I watched this, and it was at least cathartic
Sweet! Excellent work you are doing. I was just as thrilled seeing it communicate with the terminal. I remember those back in the day ;-)
Thanks! I have many fond memories of serials terminals. I was a kid during the CP/M era in the early 80s, and was a college student at the tail end of the time-sharing era in the early 90s, so I have many fond memories of using serial terminals. Good times :-)
@@davehohacks Yeah, those were the days. I remember CP/M on an S100 system--from tech school--with 8-inch floppies, LOL.
Another nice video. Thank you Dave. May I ask what baud rates you can support using the 3.6864-MHz crystal and 85C54 Timer, please? Also, are you using /16 for the baud rate clock on the 63B50 ACIA? TIA...
Sure! The way it's set up is that the CPU's E signal is fed to the 82C54 timer/counter, meaning that the 82C54 sees 1/4 of the crystal frequency, so 921.6 KHz. The 82C54 can do arbitrary integer divisions of that frequency. Dividing by 6 yields 153.6 KHz, and using the /16 mode of the 63B50 ACIA then yields 9600 bps. (Using the /1 divisor on the ACIA doesn't work, not sure why exactly.) 19.2 Kbps should be possible using a /3 divisor on the 82C54. Going with the /64 divisor on the ACIA, we should be able to get 57.6 Kbps, 28.8 Kbps, and 14.4 Kbps by using /1, /2, and /4 divisors on the 82C54 (respectively.)
Found what may be an issue with the Mem/Peri PCB vers 18 Aug 2021
I would like to preface this with.... FANTASTIC JOB.... So I am not being critical, just helping out if I can.
So I have had all the boards manufactured, built up all my F68... But found some issues with the memory/peripheral board. It may be I have a newer Kicad, but you can check and see if you are seeing the same issues.
U303 (6850) Pins 10 and 12 are supposed to be connected to Vcc and they are not connected to anything on my board.
U301 Pin 4 (PA0) is not connected to J305. The via is there, but kicad seems to think it connected at another point. Again, this may just be a Kicad thing.
I am still waiting for my Keyboard, but everything else is working....
Started building up Sound/Video card, too early to tell on that.
Keep up the great work.
Thanks for the heads up, I will check this out! The boards I had fabbed do seem to work. But, that was at least 3 versions of KiCad ago.
We really want to see the follow-up video (font) of the fpga-vga driver. ._.
It's definitely on my agenda. I've thought about it a bit, and I have a general approach in mind, but I'm still pretty new to FPGAs, so there will be some learning involved.
wow .. something worked first try .. there must be something wrong ;D
I don't know how this happened.