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Topic: Does anyone still make 8-bit microprocessors? (Read 2179 times) previous topic - next topic

Eight

Just looking around to see if anyone still makes simple 8-bit cpus like the 6800 or Z80? i.e. no built-in RAM etc. etc.

I found the Rabbit 2000, but their development environment seems to be a bit focussed on embedded systems. Could be wrong but that's the impression I was left with.

Struggling to find anything else. Any ideas?

Osgeld

#1
Sep 16, 2010, 12:01 am Last Edit: Sep 16, 2010, 12:02 am by Osgeld Reason: 1
digikey and many others still cary new model z80's (like 5 bucks for a 8mhz)

I want to say jameco has a cpu (and probably others) that pulls up when you search for 6502 and has 8080's in stock

so yea they are still out there
http://arduino.cc/forum/index.php?action=unread;boards=2,3,4,5,67,6,7,8,9,10,11,66,12,13,15,14,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,86,87,89,1;ALL

Mark S

Chips like the 1280 and 2560 support external RAM up to 64K so you could use that and build a bigger system. With the price of the chip being so low and it already having the I/O I dont see the need for a straight microprocessor.  

BTW, I used to design and program 6800/6809 series, but that was last century some time.

Mark

Eight

Wow. I didn't realise you could still buy new Z80s. It must be christmas already. :D

Although checking out that Jameco site has given me a difficult question to answer: do I go with the Z80 which I know better, or a 6800 clone (I have a long-standing loyalty to Motorola).

I'm over-joyed that I even have that choice to make. :)

Cheers Osgeld. You've made my day.

Eight

Hi Mark,

You're right in many senses - I have no need for a straight vanilla mpu. But making it a little difficult is the point of the exercise - filling in some knowledge gaps and getting back to the computing of my youth. ;)

cr0sh

Quote
With the price of the chip being so low and it already having the I/O I dont see the need for a straight microprocessor.


I guess a better question would be if there are any 8-bit microcontrollers with the ability to add addressable memory, and/or were Princeton architecture vs. Harvard...?

That is a draw about an 8-bit CPU; the fact that you can add a whole mess of memory to it, and you aren't limited in how much memory you have for programs -or- variables (plus you get the fun stuff like potentially self-modifying code and such - in other words, more bugs!).

The bad part, though, is the fact that they are real CPUs, so you need to add your own MMU scheme, address decoding, mapping things into address space, etc - the chip count and the size of your PCB goes up fast (unless you can find somebody making SMT knockoffs of the popular 8-bit CPUs - doubt it).

At a certain point, I guess you just have to "graduate" and move on to ARM or some other architecture (Nano-ITX?)...

:)
I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.

cr0sh

Heh - I just realized something; I am pretty sure Zilog still exists, and they sell a Z80-based microcontroller that is pretty much what I was pining for (more or less) - let's see...

http://www.zilog.com/

Yep - the Encore, and the eZ80...

:)
I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.

Ran Talbott

B.G. Micro has a lot of Z80 and 6800 series chips.

8-bitters have always been primarily for embedded systems:  their use in hobby computers was much like the "repurposing" of audio cassette drives for program and data storage.

westfw

There are still LOTS of vendors making various varieties of 8051, most of which can be configured to support external RAM and ROM.  Even Atmel!

cr0sh

Code: [Select]
There are still LOTS of vendors making various varieties of 8051, most of which can be configured to support external RAM and ROM.  Even Atmel!

Maybe that's what the next Arduino should be - an Atmel 8051-core controller? Maybe the AT89C5132? Ok, maybe I am dreaming, and maybe the AT89C5132 wouldn't be best (I just picked that one after some cursory datasheet reading)...

:)
I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.

James C4S

+1 on the 8051.  But I'm biased.  It was the first microprocessor I mastered.
Capacitor Expert By Day, Enginerd by night.  ||  Personal Blog: www.baldengineer.com  || Electronics Tutorials for Beginners:  www.addohms.com

westfw

The 8051 architecture is sufficiently "yucky" that most compilers are difficult to write.  I don't think there has ever been a "good" C compiler for 8051, for example (especially not a "free" one.)

What's the reason for wanting an 8051?  If you really want lots of RAM, there ARE avr versions that support it.   The Atmel XPlain eval board for xMega has 1MByte of RAM attached, for example (and I think someone had gotten some piece of the Arduino Core running on it.)

I'd rate the xMega as "most likely" to show up in new Arduino hardware; the ARM landscape is just too ... fractured.

There are other alternatives.  We (ok "they") would need to be careful not to reach a price point where we'd all be happier running Arduino sketches in usermode under linux on something like a Chumby Hacker Board, or BeagleBoard, or etc.

(Hmm.  User mode under Linux on assorted HW-hackable linux systems.  THAT'S starting to sound like an interesting idea...)

Eight

Not familiar with the 8051 - that was mainly used in industrial embedded systems right?

Most of my CPU knowledge comes from the consumer end i.e. devices used in games consoles and home computers. :D

So I'm most familiar with the Z80 (from programming the Gameboy), the 6502 (from the NES) and the 68000 (from the Amiga).

westfw

Yeah; 8051 was largely industrial.   See http://www.8052.com/
The controller chip inside your keyboard is probably an 8051 derivative.  The USB chip on a TI LaunchPad is an 8051 derivative.  They're all over the place, but they never seemed to hit the "ease of use" of PICs, AVRs, and etc.  Usually required a fancy programmer, etc.  There ARE flash-based, in-system-programmable versions, but they were sort-of late to the game and never seemed to catch on much with hobbyists...

68000 is actually another candidate for a 16/32bit Arduino-like board.  Freescale sells "Coldfire" microcontrollers based on the (lovely!) 68k architecture, and some of them support external memory and so on. The initial "Tower system" that made some jabs at the Arduino world was based on a Freescale Coldfire CPU (128 KB Flash, 24 KB RAM, Ethernet; it shoulda been sweet!)

I suspect that most semiconductor manufacturers would LOVE to know what makes something like Arduino "take off" while other systems of theoretically comparable value never seem to develop much of a community... (Hypothesis: a community requires a large number of "clueless newbies" (CN), because 1) the line between a "seasoned professional" (SP) and a CN is thinner than you think, especially if you're talking about evaluation of a new microcontroller, and 2) SPs can't admit that; it's bad for their job security; so they're afraid to ask enough questions...)

James C4S

Just came across this posting:
http://laughingsquid.com/the-6502-microprocessor-turns-35/

Included is a video of a William Shatner commercial for the VIC-20.  It's less than $300!
Capacitor Expert By Day, Enginerd by night.  ||  Personal Blog: www.baldengineer.com  || Electronics Tutorials for Beginners:  www.addohms.com

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