The 6502 Processor.

[DavidMil]

Many years ago (my wife is looking over my should and asked if this was going to be one of my caveman stories).  No Dear,

not that many years...  I wanted to build a 6502 processor using through-hole components.  I gave that up when a little research

pointed out that I would need approximately 4478 additional transistors to go with the 50 that I had, and 1019 resistors.  What

brought all this on was when I came across this interesting site:

 

www.monster6502.com

 

And it reminded me of that old idea I had.  (My wife is laughing now, but she's asking how come I can remember something

from 35 years ago, and can't remember what she asked me to do yesterday!  I'm now playing confused...).  Reading down

in the article, I noticed that to use through-hole components I would need a surface area of over a square meter.  Anyway

this is an interesting article.

 

DavidMil

 

    

[atarialoha]

The Monster 6502 is impressive work.

 

Also, if you haven't yet watched this video, I highly recommend it.

 

 

[atarialoha]

On a related note, I have yet to find an open source 6502 core to be used in FPGAs so we can run it at 100 MHz or higher.

 

I keep seeing mention of such things but never can seem to find such a virtual core to download.

[zbyti]

Nice idea! :]

Edited May 23, 2021 by zbyti

[+DjayBee]

1 hour ago, atarialoha said:

On a related note, I have yet to find an open source 6502 core to be used in FPGAs so we can run it at 100 MHz or higher.

 

I keep seeing mention of such things but never can seem to find such a virtual core to download.

Have you asked foft?

[xxl]

1 hour ago, atarialoha said:

On a related note, I have yet to find an open source 6502 core to be used in FPGAs so we can run it at 100 MHz or higher.

Eclaire does this, you can set the clock of the 6502 in bios

[Keatah]

My i9 does this. Hit the F1 key and suddenly we're playing Miniature Golf at thousands of FPS.

 

[atarialoha]

Ha! Finally found one

 

https://opencores.org/projects/cpu6502_true_cycle

[dmsc]

Hi!

19 hours ago, atarialoha said:

On a related note, I have yet to find an open source 6502 core to be used in FPGAs so we can run it at 100 MHz or higher.

 

I keep seeing mention of such things but never can seem to find such a virtual core to download.

There are a lot of 6502 cores, in Verilog and in VHDL. Two of my recommendations:

 

- The Atari 800 core by Foft uses the VHDL core from the FPGA-64 by Peter Wendrich, see http://www.64kib.com/atarixlfpga_svn/trunk/atari_800xl/common/a8core/cpu_65xx_a.vhd

- If you want a really simple and small core, in Verilog, the one by Arlet Ottens is great:  https://github.com/Arlet/verilog-6502

 

A great place to discuss about reimplementations of the 6502 is the 6502.org forum, at http://forum.6502.org/viewforum.php?f=11  There you can find TTL implementations that work replacing the original CPU, and fast TTL implementations at more than 20MHz, with full cycle accuracy.

 

Have Fun!

[atarialoha]

7 hours ago, dmsc said:

Hi!

There are a lot of 6502 cores, in Verilog and in VHDL. Two of my recommendations:

 

- The Atari 800 core by Foft uses the VHDL core from the FPGA-64 by Peter Wendrich, see http://www.64kib.com/atarixlfpga_svn/trunk/atari_800xl/common/a8core/cpu_65xx_a.vhd

- If you want a really simple and small core, in Verilog, the one by Arlet Ottens is great:  https://github.com/Arlet/verilog-6502

 

A great place to discuss about reimplementations of the 6502 is the 6502.org forum, at http://forum.6502.org/viewforum.php?f=11  There you can find TTL implementations that work replacing the original CPU, and fast TTL implementations at more than 20MHz, with full cycle accuracy.

 

Have Fun!

Thanks! This is wonderful! I am only just starting to get into FPGAs.

[JKK]

Amazing project!

 

Btw, it would be probably impossible to make replica of any of currently used processors. It would be really huge...

[+slx]

31 minutes ago, JKK said:

Btw, it would be probably impossible to make replica of any of currently used processors. It would be really huge...

Apart from the space required the size would probably cause signal latency issues as well.

[ivop]

4 minutes ago, slx said:

Apart from the space required the size would probably cause signal latency issues as well.

Yes. Maximum reliable clockrate for the monster6502 is 50kHz.