External ez80

zhulien · 10:14, 23 February 25

As it is possible to use an external cpu on the cpc, would it be possible to use an ez80 at 20mhz and just have massive wait states for internal memory accesses? But it could run full speed at the high memory.

Pollo · 11:20, 23 February 25

Why limiting yourself to the eZ80 when you can already have a powerful ARM chip plugged to the CPC with the PicoCPC, or the M4 board, etc...

zhulien · 08:10, 27 February 25

BBecause Carefully coded your same code can run on internal z80 or ez80 faster

McArti0 · 11:37, 27 February 25

I have a little interface drawn between z84c0020 and cpc with 1byte write cache.
But it is a lot of work, because basically everything has to be separated, including e.g. RD MREQ IORQ because you have to slow down the system for IO and fool GA that you are not doing anything.
So if you're going to do something like that, it's better to do everything in ARM or FPGA 20-25k LUT...

ps. But LDIR speed of 1byte per 1us from fast RAM to VRAM on a regular CPC sounds tempting...

McArti0 · 12:17, 27 February 25

Apart from that, the pinout is very problematic.

McArti0 · 12:24, 27 February 25

Regardless of the housing version ...

Sykobee (Briggsy) · 15:44, 27 February 25

Quote from: zhulien on 08:10, 27 February 25BBecause Carefully coded your same code can run on internal z80 or ez80 faster

Honestly I think a Pico could emulate a Z80 faster than an eZ80 can run.

And if you change the Pico into a task-specific accelerator (e.g., 'renderDoomScene' where all the maths and rendering to a 16KB CPC screen is done on the chip and then copied to main memory for display) it excels even more. Is this really a CPC? No, but it's been done on 8-bit console cartridges so ...

McArti0 · 18:58, 27 February 25

Without solder LQFP-100 0.5mm for true ez80.

https://www.aliexpress.com/item/1005003507004873.html

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External ez80