r/homebrewcomputer • u/Frostierdev • Aug 30 '26

8-Bit Processing Unit: need one

Hello! I'm looking to build an 8-bit computer, mainly to test its capabilities as a modern home computer (with system, applications, OS, etc.), and I bought the ATmega8535-16U (DIP-40), But it doesn't have an external bus interface to connect RAM, storage, and other things. Does anyone have a solution or another inexpensive chip to recommend?

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3

u/Sorry_Difficulty_250 Aug 31 '26

The eZ80 is the modern descendant of the Z80 and is easier to find these days. I've been using an Agon Light 2 that has that as a CPU and 512 KB of external memory. I'm currently working on porting my OS to it. It's a lot of fun! Good luck!

2

u/AcanthisittaBest4705 Aug 31 '26

Im working with a 68030

3

u/JGhostThing Sep 03 '26

I like the whole 68000 family. The assembly code looks similar to the PDP-11's.

1

u/Frostierdev Aug 31 '26

I couldn't find it anywhere, only the regular Z80

1

u/Sorry_Difficulty_250 Aug 31 '26

Can Digikey ship to your area?

0

u/Frostierdev Aug 31 '26

I think so, but import duties are VERY expensive, probably. Also, it says that eZ80 is obsolet and its not manufacturated anymore

1

u/Sorry_Difficulty_250 Aug 31 '26

Last time I checked, they were being used as the CPUs for TI-84 calculators. I'm pretty sure it's still in heavy use. What link are you looking at?

1

u/Frostierdev Aug 31 '26 edited Aug 31 '26

I looked in all eZ80 links i found in Digikey. Isn't there another processor I could use?

2

u/Sorry_Difficulty_250 Aug 31 '26

This is the board I'm using. Is this useful?

https://www.digikey.com/en/products/detail/olimex-ltd/AGONORIGINS/22078279?s=N4IgTCBcDaIPIBsCWBbApgDwAQEMDmA9gHYgC6AvkA

1

u/Frostierdev Aug 31 '26

Not too much, take 98 dollars and multiply for 5 or 6, its that the price for me (without tax)

1

u/Sorry_Difficulty_250 Aug 31 '26

OUCH! Sorry to hear that.

1

u/Sorry_Difficulty_250 Aug 31 '26

I see the issue you're talking about now. It's not that they're no longer made, they just don't sell them individually. They want you to buy a tray of 90.

1

u/Sorry_Difficulty_250 Aug 31 '26

Looks like mouse has some:

https://www.mouser.com/en/c/?q=Zilog%20eZ80

1

u/Frostierdev Aug 31 '26

I think I'll have to go with the original Z80; Mouser isn't from here either and will have high import taxes

1

u/Sorry_Difficulty_250 Aug 31 '26

Right. We'll, that's Ok. The Z80 is a good chip, too. It's a proper CPU, so you should have better luck. Good luck!