What is the Commander X8?

paulscottrobson · Post by **paulscottrobson** » Mon Mar 15, 2021 12:30 pm

"Also, the most complex functionality of the CX16p is on Vera which is neither an ASIC nor a through-hole dip chip."

Well .... actually pretty much all of the functionality of the CX16 is on Vera now. You're left with the RAM, ROM and CPU (maybe one of the sound chips, not sure).

An FPGA would have one huge advantage ; it wouldn't be limited to 8Mhz.

Wavicle · Post by **Wavicle** » Mon Mar 15, 2021 7:17 pm

6 hours ago, paulscottrobson said:

"Also, the most complex functionality of the CX16p is on Vera which is neither an ASIC nor a through-hole dip chip."

Well .... actually pretty much all of the functionality of the CX16 is on Vera now. You're left with the RAM, ROM and CPU (maybe one of the sound chips, not sure).

An FPGA would have one huge advantage ; it wouldn't be limited to 8Mhz.

Don't forget about the 128KB of high speed pseudo-dual-ported RAM on that FPGA!

I believe I had posted in another forum that consolidating functionality to VERA made the project look like an over-engineered 8 bit controller for an FPGA device; it was losing its "8 bit feel" and spec wise was competitive with 16/32 bit computers of the day.

Elektron72 · Post by **Elektron72** » Mon Mar 15, 2021 7:53 pm

7 hours ago, paulscottrobson said:

Well .... actually pretty much all of the functionality of the CX16 is on Vera now. You're left with the RAM, ROM and CPU (maybe one of the sound chips, not sure).

The 65C22 VIAs, any expansion cards, and the YM2151 (as you mentioned) are additional components of the system that are not part of VERA.

paulscottrobson · Post by **paulscottrobson** » Tue Mar 16, 2021 9:37 am

13 hours ago, Elektron72 said:

The 65C22 VIAs, any expansion cards, and the YM2151 (as you mentioned) are additional components of the system that are not part of VERA.

The VIAs are just used as control ports mostly as far as I can see. The other thing I'm not sure of is the PS/2 interface, which should be on Vera because of the way it operates.

BruceMcF · Post by **BruceMcF** » Tue Mar 16, 2021 10:49 am

1 hour ago, paulscottrobson said:

The VIAs are just used as control ports mostly as far as I can see. The other thing I'm not sure of is the PS/2 interface, which should be on Vera because of the way it operates.

One of the VIA's seem to be mostly used for PS/2 and Gamepad input ... a few of the lines are the other one are used for that, but most if it is used to provide the User port.

BruceMcF · Post by **BruceMcF** » Tue Mar 16, 2021 11:03 am

15 hours ago, Wavicle said:

Don't forget about the 128KB of high speed pseudo-dual-ported RAM on that FPGA!

I believe I had posted in another forum that consolidating functionality to VERA made the project look like an over-engineered 8 bit controller for an FPGA device; it was losing its "8 bit feel" and spec wise was competitive with 16/32 bit computers of the day.

Yes, the psuedo-video-RAM (though it is really truly dual ported) is very similar to the 80 column display on the C128 with indirect access to the Video Memory which is distinct from the main computer memory.

And similar to some of the Atari 8bits and to the C16 in having (most of) the audio functions and video functions consolidated into a single chip.

But VERA is far from the complex of coprocessor and blitter in the Amiga. Despite repeated calls from various corners in the last several years, the design team has stuck to their guns about VERA being a Video Chip rather than a Graphical Processing Unit.

picosecond · Post by **picosecond** » Tue Mar 16, 2021 11:45 am

37 minutes ago, BruceMcF said:

though it is really truly dual ported

Can you cite a source for that?

rje · Post by **rje** » Tue Mar 16, 2021 2:39 pm

On 3/15/2021 at 7:30 AM, paulscottrobson said:

pretty much all of the functionality of the CX16 is on Vera now.

...and was before. VERA is its own product too; I'd expect it to do lots of modern things.

I love the way it opens up a physical 65C02 system -- essentially doing all of the auxiliary bits from chips that can't be sourced reasonably. I think it's just a fact of this millennium that it's like a turbojet bolted onto a dune buggy. It's nice to have an embarrassment of riches!

SlithyMatt · Post by **SlithyMatt** » Tue Mar 16, 2021 2:41 pm

2 hours ago, picosecond said:

Can you cite a source for that?

https://github.com/commanderx16/x16-docs/blob/master/VERA Programmer's Reference.md

picosecond · Post by **picosecond** » Tue Mar 16, 2021 3:01 pm

15 minutes ago, SlithyMatt said:

https://github.com/commanderx16/x16-docs/blob/master/VERA Programmer's Reference.md

Those are logical ports, and maybe that is what Bruce meant by "truly dual-ported". I inferred he was describing the internal construction of the FPGA RAM blocks.