Pages: [1]   Go Down
Author Topic: Programming x86-arch chips (CPUs)  (Read 409 times)
0 Members and 1 Guest are viewing this topic.
Offline Offline
Newbie
*
Karma: 0
Posts: 14
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Before you decide to go off on a rant on me for how impractical it is, bear in mind that I have at least 3 different computers from 3 different eras (486, Pent II, AMD Ath) of the x86 architecture, and these things are doing nothing but sitting around gathering dust.

I wanted to tinker a bit with programming these chips and using them almost pseudo-MCU, just to learn a bit about how they're coded and a bit more about the architecture. I've studied it well enough to know key components of it, but never actually sat down and looked at an assembler.

Anyone got any resources for something like this? Again, these things are in 3 different stages of obsolescence and will continue to gather dust (and eventually be pitched). Might as well do some sacrificial, fun learning with them.
Logged

Massachusetts, USA
Offline Offline
Tesla Member
***
Karma: 202
Posts: 8719
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

The firmware alone isn't enough for any significant software development.  You will need an operating system.  If you want to get close to the hardware you could install FreeDOS (freedos.org) or a Linux distribution (http://distrowatch.com).
Logged

Send Bitcoin tips to: 1L3CTDoTgrXNA5WyF77uWqt4gUdye9mezN
Send Litecoin tips to : LVtpaq6JgJAZwvnVq3ftVeHafWkcpmuR1e

Global Moderator
Boston area, metrowest
Offline Offline
Brattain Member
*****
Karma: 525
Posts: 26554
Author of "Arduino for Teens". Available for Design & Build services. Now with Unlimited Eagle board sizes!
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

You don't program microprocessors directly. You program the (EE)PROM that is on their address bus.
Remember BIOS? The uP resets and runs code in the BIOS and from there jumps out to larger memory (CD, floppy, hard drive).
You also need RAM (usually DRAM) to complement any on-chip RAM.
Seems like first step would be getting some BIOS code written.
Logged

Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

Offline Offline
Newbie
*
Karma: 0
Posts: 14
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

You don't program microprocessors directly. You program the (EE)PROM that is on their address bus.
Remember BIOS? The uP resets and runs code in the BIOS and from there jumps out to larger memory (CD, floppy, hard drive).
You also need RAM (usually DRAM) to complement any on-chip RAM.
Seems like first step would be getting some BIOS code written.


Sorry for the delay -

First question to ask would probably be along the lines of how is the BIOS constructed? (i.e. is it written in an assembler, and what does it contain in an usual implementation?)

That being established, would it be possible to "use" a micro as a MCU provided it is socketed to the mobo with access to RAM/cache memory and peripheral/IO interfaces?
Logged

Global Moderator
Boston area, metrowest
Offline Offline
Brattain Member
*****
Karma: 525
Posts: 26554
Author of "Arduino for Teens". Available for Design & Build services. Now with Unlimited Eagle board sizes!
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

1st question - I don't know. PCs have a lot going on with floppy, CD, hard drive, video, USB, etc. all being set up via the BIOS.

2nd question - sure. I put a 68020 on a board to set up memory and write to all the addresses to ensure valid error detection and correction values at each location prior to the system accessing the memory.
Logged

Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

Pages: [1]   Go Up
Jump to: