msx hardware projects

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Van legacy

Hero (570)

afbeelding van legacy

04-10-2007, 17:04

Maybe there is an equivalent for it with the same instruction set??? I mean for the Z380.

Van Poltergeist

Champion (279)

afbeelding van Poltergeist

04-10-2007, 17:56

I think snout realised that rumors are spreading among a few persons, like msd, Latok,wolf_ and patsie that indicate the z380 is no longer produced...

Isn't the eZ80 a viable solution then?

Van msd

Paragon (1508)

afbeelding van msd

04-10-2007, 18:54

Yes the z380 is no longer on the zilog website. ez80 can be usefull too.

Van Edevaldo

Master (143)

afbeelding van Edevaldo

01-10-2018, 18:57

Quote:

I think snout realised that rumors are spreading among a few persons, like msd, Latok,wolf_ and patsie that indicate the z380 is no longer produced...

Rumors were largely exaggerated at that time! ;-) Z380 was still being produced by middle 2016 and may still be in production today.

Quote:

Isn't the eZ80 a viable solution then?

I don't think so. It is not completely impossible but require lot's of hardware wizardry. The ez80 uses most IO ports internally.
So a HW emulation mechanism that catches the instructions on the fly and modify them while remapping IO addresses is needed. For that you would need a sizable CPLD. And once you get that, just do the Z80 in an FPGA.

For prototypes and small runs Z380 may still be an interesting options. The one thing I dislike about it is that it has the Z80 mode and a 32bit mode but you cannot change dynamically between them. Once set only a reset can change it.

Van Grauw

Ascended (10639)

afbeelding van Grauw

01-10-2018, 19:03

Well, you can add some supporting logic which signals a reset and sets a flag to indicate it's a soft reset... Then the BIOS can continue at an address specified in memory. I imagine that's how it works on the turboR as well...

Van erpirao

Paragon (1292)

afbeelding van erpirao

01-10-2018, 20:53

Edevaldo wrote:
Quote:

I think snout realised that rumors are spreading among a few persons, like msd, Latok,wolf_ and patsie that indicate the z380 is no longer produced...

...

Quote:

Isn't the eZ80 a viable solution then?

...
I don't think so. It is not completely impossible but require lot's of hardware wizardry. The ez80 uses most IO ports internally.
...

I think the ez80 would be a great solution for an external acceleration device in the super-fx style of snes or svg of sega megadrive.
a z80 much faster than performing the calculations would be a wonder

Van zett

Hero (608)

afbeelding van zett

01-10-2018, 21:25

dont use things like that. make a r800 in vhdl and make a update after that. staing on z80 is not good. lot of problems are dealed with for msx with the r800

Van Edevaldo

Master (143)

afbeelding van Edevaldo

01-10-2018, 22:55

Quote:

I think the ez80 would be a great solution for an external acceleration device in the super-fx style of snes or svg of sega megadrive.
a z80 much faster than performing the calculations would be a wonder

True, but in that case it does not need to be Z80 compatible. Anything with a good C/C++ compiler and 32-bit linear addressing and maybe an FPU would simplify software development immensely.

Any arm microcontroller runs significantly faster than an eZ80 would, include their own memory RAM/Flash and some peripherals.

Van Edevaldo

Master (143)

afbeelding van Edevaldo

01-10-2018, 22:50

Quote:

Well, you can add some supporting logic which signals a reset and sets a flag to indicate it's a soft reset... Then the BIOS can continue at an address specified in memory. I imagine that's how it works on the turboR as well...

This is certainly possible! Good idea.
When I was looking into that I wanted to be able to run some sort of 32-bit environment to support MSX software development. Like a 32-bit OS running on a Z380 able to run Z80 threads with debug support, pause, step, etc, in a more protected environment. It would be a nice possible evolution to the MSX hardware.

To do that with the Z380, any time you switch to a Z80 thread you have to go through such reset. I do not know how long the Z380 takes to reset and how much state needs to be saved/restored. But it could be possible as long as you don't do it too often.

Of course openMSX gives you a lot of that as well. But I have more fun with the hardware... ;-)

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