embedded systems skills set

I have some interests in embedded systems and I want to learn more. I
expect most embedded systems are implemented in either C or C++.
Basically Java is not an appropriate langauge in embedded system.
Correct? Also, a good embedded systems programmer is expected to
understand software and hardware system well? Is device driver related
to embedded system? What kind of skills set you recommend if I want to
work in this field?

please advice. thanks!!

John wrote:
> I have some interests in embedded systems and I want to learn more. I
> expect most embedded systems are implemented in either C or C++.
> Basically Java is not an appropriate langauge in embedded system.
> Correct?

There are different classes of embedded systems. Some of them are
high-end and they can run linux. Others are very small and they have no
OS.

The high-end devices can definitely run Java, and I think many cell
phones are in this category. But C is by far the most popular language
for embedded systems. C++ is used sometimes, also.

Of course, you'll need to learn a lot about Microcontrollers and the
various architectures. Although I'm not a fan of PIC devices in
general, they are extremely popular and the Parallax company has great
learning packages. You could get one of the educational Basic Stamp
packages and this will give you a feel for these things.

Eric

On 16 Sep 2006 19:13:48 -0700, John wrote:
/cut

IMHO best way to learn some architecture is by programming in assembly
language. 

You are forced to think like a machine. 
I program my systems in assembly and C. I know a little of C++ but C is OK
for me.

Mad I.D. wrote:
> On 16 Sep 2006 19:13:48 -0700, John wrote:
> /cut
>
> IMHO best way to learn some architecture is by programming in assembly
> language.


>
> You are forced to think like a machine.

I completely agree, which is why you'll find a lot of people with
hardware backgrounds in deep embedded positions, by which I mean the
jobs where one writes bare metal code or low level drivers.

An intimate knowledge of how the hardware works is a definite advantage
for those things.

As the definition of 'embedded systems' has expanded (morphed, some
might say), it's not uncommon to find applications programmers doing a
lot of code - in a cell phone or something running Linux, for instance,
there's no need to know the hardware to implement an application that
merely uses the resources provided.

Applications programming, incidentally, is just as important as the
driver programming; it all depends on just what sort of embedded system
one ends up with :)

My personal preference depends on what I am writing; assembly language
for where there is no OS, doing boot setups or in some cases where I
have to oustmart a compiler that's just a little too smart for it's own
good (optimising out some instruction sequences that are necessary at
the hardware layer comes to mind where the compiler doesn't necessarily
obey the compiler directives ;)

Other than that, I'm personally most comfortable with C, but I've seen
Java, C++, C#, .net, and a host of other languages / platforms used in
the embedded space.

Cheers

PeteS


> I program my systems in assembly and C. I know a little of C++ but C is OK
> for me.

In article <1158462734.847309.225660@k70g2000cwa.googlegroups.com>, Eric 
<englere_geo@yahoo.com> writes
>
>John wrote:
>> I have some interests in embedded systems and I want to learn more. I
>> expect most embedded systems are implemented in either C or C++.
>> Basically Java is not an appropriate langauge in embedded system.
>> Correct?
>
>There are different classes of embedded systems.

Yes

>Some of them are
>high-end and they can run linux.

Some run an OS  There are many OS about from Embedded XP, Unix and 
clones (ie Linux) and many others  down to small schedulers some are 
Real Time and others are not.

These are from 8 bit to 128 bit systems.

> Others are very small and they have no
>OS.

Others have no OS these are also 8-128 bit systems.

There are OS 0n 8 bit systems and some 64 bit systems don't use an OS. 
Though as a rule the larger systems tend to use an OS.

>The high-end devices can definitely run Java,

Not always true.  However some 8 bit devices do.

>and I think many cell
>phones are in this category
???? Mobile phones use many MCU (usually)  more than  one.  I know a lot 
of the SIm cards can run Java and they are 8 bit.


>. But C is by far the most popular language
>for embedded systems. C++ is used sometimes, also.

Yes.

>Of course, you'll need to learn a lot about Microcontrollers and the
>various architectures. Although I'm not a fan of PIC devices in
>general, they are extremely popular

Well they are used.... Though the 8051 is far more common.


-- 
\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
\/\/\/\/\ Chris Hills  Staffs  England     /\/\/\/\/
/\/\/ chris@phaedsys.org      www.phaedsys.org \/\/\
\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/

thanks for all your inputs.

Since there are different classes of embedded systems, when people talk
about embedded systems, it actually can mean low-level system
programming, and high-level application programming as well?

Do we consider embedded systems development as hardware development, or
software development, or both? It seems to me its a mixture of software
and hardware development. And it depends on which area we work on, the
more lower level we work on, then it tend to need more hardware
background?

please advice more. thanks...

John wrote:
> thanks for all your inputs.
> 
> Since there are different classes of embedded systems, when people talk
> about embedded systems, it actually can mean low-level system
> programming, and high-level application programming as well?
> 
> Do we consider embedded systems development as hardware development, or
> software development, or both? It seems to me its a mixture of software
> and hardware development. And it depends on which area we work on, the
> more lower level we work on, then it tend to need more hardware
> background?
> 
> please advice more. thanks...
> 

I think the essence of an embedded system is that it's invisible,
buried inside some widget. The realm of possibilities fitting this
is huge, and includes everything you've suggested. What do you
want to do -- hardware or software? You can be effective working
in embedded systems if you're good at either one alone, or both.

It's not PC software -- people don't need to install it or fight an OS.
You apply power and it's just there doing its thing. You don't have
monthly updates -- if the thing was so buggy to begin with right off
the bat you'll probably tank anyway.

There's no pat answer. The more you know and the wider range, the
more effective you can be. You'll be able to apply diverse knowledge
to every problem. It's all one of degrees + balance. When you work out,
you don't just lift weights with your right arm, do you?

-Dave


-- 
David Ashley                http://www.xdr.com/dash
Embedded linux, device drivers, system architecture

"John" <javacc1@gmail.com> wrote in message 
news:1158533706.714740.146170@e3g2000cwe.googlegroups.com...
> thanks for all your inputs.
>
> Since there are different classes of embedded systems, when people talk
> about embedded systems, it actually can mean low-level system
> programming, and high-level application programming as well?
>
> Do we consider embedded systems development as hardware development, or
> software development, or both? It seems to me its a mixture of software
> and hardware development. And it depends on which area we work on, the
> more lower level we work on, then it tend to need more hardware
> background?

I'm an embedded specialist. This means I deal with everything from 8-bit 
micros running in 8k of RAM, right up to embedded PCs running a BSD 
variant - even, may dog forgive me, Windows CE. I'm also a hardware guy, so 
the smaller systems I design myself - but the higher-end systems I buy and 
bury in a box.

Probably the key thing about embedded is that it's a box with a specific 
function - it's *not* a machine you can run anything on. It probably won't 
have a keyboard, screen, mouse, in the accepted sense. It has one job to 
do - e.g. a temperature controller, or a router, or a washing machine. One 
tends not to run "Solitaire" on a washing machine. (So far, anyway.)

Steve
http://www.fivetrees.com 

John wrote:
> I have some interests in embedded systems and I want to learn more. I
> expect most embedded systems are implemented in either C or C++.
> Basically Java is not an appropriate langauge in embedded system.
> Correct? Also, a good embedded systems programmer is expected to
> understand software and hardware system well? Is device driver related
> to embedded system? What kind of skills set you recommend if I want to
> work in this field?

To add to what others have said, I would recommend that you buy a
development board based on a small, simple micro architecture, and
start programming it.  The 8051, AVR, HC11 or HC12 are some possible
micro families.  Get a board with an LCD and keypad and some analog IO
in addition to the digital IO.  Program it to do anything you can think
of.  To get more ideas, search around the web for class notes posted by
the professors of university embedded programming classes.  Start
programming in assembly, then move to C.  Many boards will come with at
least a restricted-capacity compiler.

As one example, there's this board:
http://www.evbplus.com/dragon12.html

I've never seen one of these in person, but the amount and kinds of IO
make it look like a nice board for starting embedded stuff, and the
HCS12 core architecture and instruction set is very clean, making it a
good choice to learn assembly programming, IMO.  Look around the web
and you'll find a great many other board vendors as well.

On Monday, in article <m7CdnbSpZ-p5d5DYRVnyhw@pipex.net>
     steve@NOSPAMTAfivetrees.com "Steve at fivetrees" wrote:
>"John" <javacc1@gmail.com> wrote in message
>news:1158533706.714740.146170@e3g2000cwe.googlegroups.com...
>> thanks for all your inputs.
>>
>> Since there are different classes of embedded systems, when people talk
>> about embedded systems, it actually can mean low-level system
>> programming, and high-level application programming as well?
>>
>> Do we consider embedded systems development as hardware development, or
>> software development, or both? It seems to me its a mixture of software
>> and hardware development. And it depends on which area we work on, the
>> more lower level we work on, then it tend to need more hardware
>> background?
>
>I'm an embedded specialist. This means I deal with everything from 8-bit 
>micros running in 8k of RAM, right up to embedded PCs running a BSD 
>variant - even, may dog forgive me, Windows CE. I'm also a hardware guy, so 
>the smaller systems I design myself - but the higher-end systems I buy and 
>bury in a box.
>
>Probably the key thing about embedded is that it's a box with a specific 
>function - it's *not* a machine you can run anything on. It probably won't 
>have a keyboard, screen, mouse, in the accepted sense. It has one job to 
>do - e.g. a temperature controller, or a router, or a washing machine. One 
>tends not to run "Solitaire" on a washing machine. (So far, anyway.)

I have seen problems at aerospace companies, where systems for testing
equipment and components, gets messed up too often because they can
install screen savers, play games.... Then they wonder why their tester
does not work!

-- 
Paul Carpenter          | paul@pcserviceselectronics.co.uk
<http://www.pcserviceselectronics.co.uk/>    PC Services
<http://www.gnuh8.org.uk/>              GNU H8 & mailing list info
<http://www.badweb.org.uk/>             For those web sites you hate