Re: [OT] Re: writing a dailer in c for a 8051 based system

From: Dan Pop (Dan.Pop_at_cern.ch)
Date: 05/26/04 

Date: 26 May 2004 13:41:15 GMT

In <pan.2004.05.26.09.52.12.812641@sig.now> August Derleth <see@sig.now> writes:

>On Wed, 26 May 2004 02:57:59 +0100, Malcolm wrote:
>
>> What's an 8051? Is there an ng devoted to it?
>
>It's a microcontroller[1] made by Intel. It is (or was) widely used in
>things like keyboards and modems and microwaves and so on and so forth.
>
>The best place to discuss 8051-related stuff is probably
>comp.arch.embedded.
>
>[1]A microchip designed to be used in an environment other than a PC,
>server, router, or other obviously-computer environment.

Many older hard disks found in PC's used an 8051 chip, so your definition
is rather shaky. Furthermore, Intel had an 8052 chip with an embedded
BASIC interpreter, that could be used as the core of a small computer.

>They typically
>have a place to hardcode instructions (that is, onboard ROM space) and
>might support odd word sizes to interface with specialty hardware.

This is not the case of the general purpose ones, like the 8051, which
are best described as single chip computers, containing a CPU, ROM, RAM
and various external interfaces on a single chip. The word sizes are
the vanilla ones, so that adding external ROM or RAM can be done using
cheap, off the shelf, components (no point in having a cheap
microcontroller if it needs expensive external chips).

>Low
>power consumption and extremely low cost-per-chip often counts for more
>than clock speed.

Low power consumption is often not an issue (no point in using a < 1 mW
controller in a microwave oven) but low cost per chip is an overriding
concern, otherwise the designer would opt for a traditional microprocessor
+ ROM + RAM + I/O intefaces approach, which is often more comfortable to
program on (the typical CPU in a microcontroller is less capable than an
usual microprocessor, the program and the data often reside in different
address spaces, and, for machine code compactness reasons, the program
memory is often paged).

Dan 

-- 
Dan Pop
DESY Zeuthen, RZ group
Email: Dan.Pop@ifh.de

Relevant Pages

  • Re: [OT] Re: writing a dailer in c for a 8051 based system
    ... >things like keyboards and modems and microwaves and so on and so forth. ... Many older hard disks found in PC's used an 8051 chip, ... are best described as single chip computers, containing a CPU, ROM, RAM ...
    (comp.lang.c)
  • Re: 6522 broken. Is it a common issue on Vectrex?
    ... adjacent pulses, followed by a 0V region, then two 5V pulses again, ... I'll try removing the AY chip and re-test again. ... but only if your ROM and RAM already works (as the ROM ...
    (rec.games.vectrex)
  • Re: welchen Fahrradcomputer, Tacho
    ... Ein Prozessorkern dürfte zu teuer sein, also wird ein Chip ... oder 4bit-MCU, wenige Bytes RAM, Programm aus dem ROM. ... ohne verschiedene ASICS haben zu müssen. ...
    (de.rec.fahrrad)
  • Re: Desoldering Apple IIc RAM chips
    ... any ram problems otherwise with the IIc. ... Depending on the type of RAM fault, I can see how that might work. ... I just de-soldered another RAM chip. ... also upgraded the ROM the from original to ROM 00. ...
    (comp.sys.apple2)
  • Re: how can a bit be off in memory?
    ... guess would be a bit got flipped in RAM, the page of RAM that held the ... and through the plastic of a RAM chip? ... cause problems would be gamma rays (cosmic rays). ... The unstable isotope of lead would decay to things that were either stable ...
    (comp.os.linux.misc)