securitybreach Posted March 28, 2012 Share Posted March 28, 2012 I just ran across this neat article on how to run Linux on an 8bit microcontroller: Linux on an 8-bit micro? Intro It is common to see newbies asking in microcontroller forums if they can run Linux on their puny little 8-bit micro. The results are usually laughter. It is also common to see, in Linux forums, asked what the minimum specs for Linux are. The common answer is that it requires a 32-bit architecture and an MMU and at least a megabyte of ram to fit the kernel. This project aims to (and succeeds in) shatter(ing) these notions. The board you see on the right is based on an ATmega1284p. I've made one with an ATmega644a as well, with equal success. This board features no other processor and boots Linux 2.6.34. In fact, it can even bring up a full Ubuntu stack, including (if you have the time) X and gnome.... http://dmitry.co/index.php?p=./04.Thoughts...nux%20on%208bit I may have to try this one day Quote Link to comment Share on other sites More sharing options...
V.T. Eric Layton Posted March 28, 2012 Share Posted March 28, 2012 What is that actual processor that he's using. I don't see where he says anywhere. Quote Link to comment Share on other sites More sharing options...
securitybreach Posted March 29, 2012 Author Share Posted March 29, 2012 What is that actual processor that he's using. I don't see where he says anywhere. CPU All that's left is that pesky 32-bit CPU & MMU requirement. Well the AVR has no MMU and is 8-bit. To conquer this obstacle, I wrote an ARM emulator. ARM is the architecture I am most familiar with, and it's simple enough that I could comfortably write an emulator for it. Why write one instead of porting one? Well, porting someone else's code is no fun, plus none of the emulators I saw out there were written in a way that would make them easy to port to an 8-bit device. One of the factors: AVR compiler insists on making ints 16-bit so something as simple as "(1 Quote Link to comment Share on other sites More sharing options...
V.T. Eric Layton Posted March 29, 2012 Share Posted March 29, 2012 What is that 40 pin chip on that board? Quote Link to comment Share on other sites More sharing options...
securitybreach Posted March 29, 2012 Author Share Posted March 29, 2012 What is that 40 pin chip on that board? I am not for sure but here is more info on the microcontroller: http://www.atmel.com/devices/ATMEGA644A.aspx Quote Link to comment Share on other sites More sharing options...
V.T. Eric Layton Posted March 29, 2012 Share Posted March 29, 2012 Hmm... well, they're not giving a parts list anywhere in the documentation, which tells me that they want you to buy their kits. I was just wondering because I have some of these older CPUs, CMOS, and TTL type chips out in my shop. Once I inventory the carp out there, most of it will be going on eBay shortly. Quote Link to comment Share on other sites More sharing options...
securitybreach Posted March 29, 2012 Author Share Posted March 29, 2012 Hmm... well, they're not giving a parts list anywhere in the documentation, which tells me that they want you to buy their kits. I was just wondering because I have some of these older CPUs, CMOS, and TTL type chips out in my shop. Once I inventory the carp out there, most of it will be going on eBay shortly. Well after skimming the article, these are the specs: A 1GB SD card works fine, though 512Mb would be enough for this particular file system (Ubuntu Jaunty). ATmega1284p board http://www.atmel.com/products/microcontrol...vr/megaAVR.aspx serial port for mouse/keyboard CPU is emulated First let's address the RAM. As you can see, there is an antique 30-pin SIMM memory module on the board. These were in use for 80286-based PCs. It is interfaced to the ATmega, and I wrote the code to access it as well as refresh it within spec (SDRAM requires constant refreshing to avoid losing data). Quote Link to comment Share on other sites More sharing options...
securitybreach Posted March 29, 2012 Author Share Posted March 29, 2012 He also provides the source code for the project: It is a bit of a mess, but it does work. Get it while it's hot: LINK. The license is simple: For non-commercial use, as long as you keep the licence file with the source and publish all your changes, we're cool. For commercial use, talk to me, and we'll agree on something. To build the emulator to try it on the PC type "make". To run use "./uARM DISK_IMAGE". To build optimized PC version use "make BUILD=opt". to build for AVR use "make BUILD=avr". It currently targets ATmega1284p. To target ATmega644, besides the makefile change, reduce the numbers in icache.h so that the icache is small enough to fit in the internal RAM in the 644. Included in the archive is the final hex file for the 1284p as well. Quote Link to comment Share on other sites More sharing options...
V.T. Eric Layton Posted March 29, 2012 Share Posted March 29, 2012 No chip numbers, though. That's what I'm curious about. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.