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Scott
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 Posted: Sun Nov 09, 2008 6:41 pm Post subject: New to Embedded Software |
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Hi,
Sorry in advance if this is the wrong place for this question.
I am a 24 year old, Software Developer who has a 2.1 in BSc (Hons)
Software Development. I have been working solely on CRUD applications
during the 3 years I have been working and I have decided its time for
a change of direction in my career.
I would really like to begin working with Embedded/Real Time systems,
but my programming experience is with Delphi which is really a
programming language for RAD applications and I doubt it would be
suited to Embedded/Real Time systems.
I guess what I would really like to know is how to go about changing
the direction of my career, what programming languages do I need to
know, which operating systems is it best to use etc.
Any help is really welcome.
Thanks
Scott |
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Scott
Guest
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| Posted: Sun Nov 09, 2008 7:00 pm Post subject: Re: New to Embedded Software |
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| Quote: | Did you have a narrower idea of where you wanted to fit into the spectrum?
I guess I would like to work on projects with a real scientic twist, |
during my university work placement I go to write software that
interacted with a time domain reflectrometry probe to measure oil
levels in water coolant pumps in Nuclear reactors. Something similar
in nature would be great but I am open minded. |
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Mike Silva
Guest
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| Posted: Sun Nov 09, 2008 7:43 pm Post subject: Re: New to Embedded Software |
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On Nov 9, 1:41 pm, Scott <ScottDSell...@googlemail.com> wrote:
| Quote: | Hi,
Sorry in advance if this is the wrong place for this question.
I am a 24 year old, Software Developer who has a 2.1 in BSc (Hons)
Software Development. I have been working solely on CRUD applications
during the 3 years I have been working and I have decided its time for
a change of direction in my career.
I would really like to begin working with Embedded/Real Time systems,
but my programming experience is with Delphi which is really a
programming language for RAD applications and I doubt it would be
suited to Embedded/Real Time systems.
I guess what I would really like to know is how to go about changing
the direction of my career, what programming languages do I need to
know, which operating systems is it best to use etc.
Any help is really welcome.
Thanks
Scott
|
You'll probably get lots of advice, much of it conflicting. With that
warning, what I'd do is to start with two uC families, an 8-bit
(suggest 80C51 or AVR) and a 32-bit (suggest ARM7). Get a simple
development board for each family, one with buttons, leds, an LCD
character display, and whatever else catches your fancy). Find
suitable software tools (the board mfgr can point you in the right
direction) and start writing simple programs - you can find lots of
ideas on the net. As was mentioned, C is the primary language you
will need to learn because it is ubiquitous in the embedded field.
Having said that, you should also learn enough about the assembly
languages of your chosen families to be able to at least understand
the code produced by the compiler. I'd even recommend you write a
couple of small programs in assembly, because I think you'll get a
better sense of what's happening under the hood. Others may disagree.
One critical skill you will need to learn is how to use interrupts.
Become comfortable using interrupts for timing, communications and
other events. Get a feel for doing the time-critical work inside the
interrupt while leaving additional work to be done in the background.
Learn how to access interrupt-read and interrupt-written data safely.
Learn about "volatile".
Finally, install an RTOS on one of your boards (the ARM board would be
my choice), and learn how to write responsive embedded software on top
of an RTOS. Responsiveness is one of the keys in the embedded world,
RTOS or no RTOS. Being frugal with limited system resources is
another - things like not filling up your limited RAM with strings
that could live in flash, making judicious use of 8-bit variables (and
even bit variables) on 8-bit devices, etc.
It's a fun and interesting field. Good luck!
Mike |
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Mike Silva
Guest
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| Posted: Sun Nov 09, 2008 8:30 pm Post subject: Re: New to Embedded Software |
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On Nov 9, 2:40 pm, Rich Webb <bbew...@mapson.nozirev.ten> wrote:
| Quote: | Sparkfun has a lot of dev boards and project ideas. A good "get your
feet wet" project could be to read the voltage at an A/D port and
display the results on a generic HD44780-based character LCD display
(these are widely available as inexpensive "surplus" if you're not
overly particular about the size of the display).
|
Funny you should suggest that. I just wired up a little comms test
unit with an AVR ATmega48, 3 slide pots and an LCD display, to send
out test commands and data over an RS485 line. The LCD display comes
from a batch I must have bought 20 years ago, and then forgot I had
them. It works just fine. The linear slide pots I just bought from
Mouser, OTOH, turn out to be audio taper. Oh well, not a big deal for
my purposes.
Mike |
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FreeRTOS.org
Guest
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| Posted: Mon Nov 10, 2008 12:55 am Post subject: Re: New to Embedded Software |
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"Scott" <ScottDSellers@googlemail.com> wrote in message
news:914183aa-24fc-4db0-ba0d-4b274ab37bf6@c36g2000prc.googlegroups.com...
| Quote: | Hi,
Sorry in advance if this is the wrong place for this question.
I am a 24 year old, Software Developer who has a 2.1 in BSc (Hons)
Software Development. I have been working solely on CRUD applications
during the 3 years I have been working and I have decided its time for
a change of direction in my career.
I would really like to begin working with Embedded/Real Time systems,
but my programming experience is with Delphi which is really a
programming language for RAD applications and I doubt it would be
suited to Embedded/Real Time systems.
I guess what I would really like to know is how to go about changing
the direction of my career, what programming languages do I need to
know, which operating systems is it best to use etc.
Any help is really welcome.
Thanks
|
Embedded systems is itself a huge topic with a vary wide scope - talking
toys to UAV's all come under the real time banner. Did you have a narrower
idea of where you wanted to fit into the spectrum?
C is still king in the lower end embedded market. I would suggest buying
yourself some cheap hardware that comes with good demos that you can get
your teeth into. Demo and eval hardware is now often sold at what must be
cost price, so you can buy a selection. You can download free and
evaluation versions of compilers too so can get up and running for very
little cost. The Demos section of the FreeRTOS.org WEB site provides plenty
of example low cost tool chains and hardware.
--
Regards,
Richard.
+ http://www.FreeRTOS.org & http://www.FreeRTOS.org/shop
17 official architecture ports, more than 6000 downloads per month.
+ http://www.SafeRTOS.com
Certified by TÜV as meeting the requirements for safety related systems. |
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Mike Silva
Guest
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| Posted: Mon Nov 10, 2008 12:55 am Post subject: Re: New to Embedded Software |
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On Nov 9, 6:01 pm, Rich Webb <bbew...@mapson.nozirev.ten> wrote:
| Quote: |
The HD44780 interface, though, is a good learning tool. RS, R/W* and E
do what? How does the crazy initialization work? Read the busy bit or do
fixed intervals? If the busy bit, what to do if the display is unplugged
and not-busy never occurs? Embedded development means it's embedded in
or with something else and understanding the incomplete, incorrect, or
contradictory documentation for that something else, and often building
a benchtop model of parts of it, is a big part of the game.
|
Right, and if doing fixed intervals, how do you wait 40us between
chars? For that matter, how do you generate a 500ns E pulse on a 20
or 60 or 100 MHz processor? It actually takes a bit of thinking.
But once you've got the display running you've got a great debugging
aid. And if you (the newbie) can create an HH:MM:SS display that
keeps correct time using a timer interrupt, and only updates the
display when a change occurs, and can do other processing in the
background, you're well on your way.
Mike |
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Rich Webb
Guest
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| Posted: Mon Nov 10, 2008 1:40 am Post subject: Re: New to Embedded Software |
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On Sun, 9 Nov 2008 10:41:49 -0800 (PST), Scott
<ScottDSellers@googlemail.com> wrote:
| Quote: | Hi,
Sorry in advance if this is the wrong place for this question.
I am a 24 year old, Software Developer who has a 2.1 in BSc (Hons)
Software Development. I have been working solely on CRUD applications
during the 3 years I have been working and I have decided its time for
a change of direction in my career.
I would really like to begin working with Embedded/Real Time systems,
but my programming experience is with Delphi which is really a
programming language for RAD applications and I doubt it would be
suited to Embedded/Real Time systems.
I guess what I would really like to know is how to go about changing
the direction of my career, what programming languages do I need to
know, which operating systems is it best to use etc.
Any help is really welcome.
|
Buy a few development boards and compilers and then build things. If
these things won't be on your work-related resume, perhaps put up a
"things I built and how I built them" web page to show prospective
employers that you're not "just" a Delphi developer.
Languages: C and assembler.
Operating systems. None. This is work at the bare metal level.
Know your way around an oscilloscope and logic analyzer. Be able to
design and build your own interface circuits and read/understand the
schematics for the things to which you'll be interfacing.
Sparkfun has a lot of dev boards and project ideas. A good "get your
feet wet" project could be to read the voltage at an A/D port and
display the results on a generic HD44780-based character LCD display
(these are widely available as inexpensive "surplus" if you're not
overly particular about the size of the display).
For chips, my own preference in the 8/16/32 bit categories are Atmel
AVR, TI MSP 430, and NXP LPC2000 ARM7s. Your mileage may vary. I like
Imagecraft compilers for all of these but there are many other options,
including flavors of gcc.
http://www.sparkfun.com/commerce/categories.php
http://www.imagecraft.com/
http://www.avrfreaks.net/
http://www.embeddedrelated.com/
--
Rich Webb Norfolk, VA |
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Rich Webb
Guest
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| Posted: Mon Nov 10, 2008 5:01 am Post subject: Re: New to Embedded Software |
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On Sun, 9 Nov 2008 12:30:55 -0800 (PST), Mike Silva
<snarflemike@yahoo.com> wrote:
| Quote: | On Nov 9, 2:40 pm, Rich Webb <bbew...@mapson.nozirev.ten> wrote:
Sparkfun has a lot of dev boards and project ideas. A good "get your
feet wet" project could be to read the voltage at an A/D port and
display the results on a generic HD44780-based character LCD display
(these are widely available as inexpensive "surplus" if you're not
overly particular about the size of the display).
Funny you should suggest that. I just wired up a little comms test
unit with an AVR ATmega48, 3 slide pots and an LCD display, to send
out test commands and data over an RS485 line. The LCD display comes
from a batch I must have bought 20 years ago, and then forgot I had
them. It works just fine. The linear slide pots I just bought from
Mouser, OTOH, turn out to be audio taper. Oh well, not a big deal for
my purposes.
|
Yup. I agree with your earlier post that one of the first things to
learn is how to properly interact with a chip's interrupt structure. My
generic Hello, World for a new microcontroller (and, I suspect, many
other folks do this too) is to toggle a selected I/O pin at a 1 Hz rate
based on a timer interrupt. That gets most of the kinks out of the tool
chain and gives a basic understanding of the chip and its peripherals.
The HD44780 interface, though, is a good learning tool. RS, R/W* and E
do what? How does the crazy initialization work? Read the busy bit or do
fixed intervals? If the busy bit, what to do if the display is unplugged
and not-busy never occurs? Embedded development means it's embedded in
or with something else and understanding the incomplete, incorrect, or
contradictory documentation for that something else, and often building
a benchtop model of parts of it, is a big part of the game.
--
Rich Webb Norfolk, VA |
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Charlie Springer
Guest
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| Posted: Mon Nov 10, 2008 8:40 am Post subject: Re: New to Embedded Software |
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On Sun, 9 Nov 2008 11:00:25 -0800, Scott wrote
(in article
<370c19d5-c226-4318-a8c3-9829c8a2cd28@35g2000pry.googlegroups.com>):
| Quote: | Did you have a narrower idea of where you wanted to fit into the spectrum?
I guess I would like to work on projects with a real scientic twist,
during my university work placement I go to write software that
interacted with a time domain reflectrometry probe to measure oil
levels in water coolant pumps in Nuclear reactors. Something similar
in nature would be great but I am open minded.
|
Get any little development board with a PIC or AVR from Sparkfun. The PIC
folks used to have a board that has a nice little compiler and all the
goodies. You don't want to get frustrated setting up and debugging a GCC
environment. Get one with a TFT display and an A/D converter. Assign yourself
the task of making it into a digital oscilloscope and a voltmeter and a
frequency meter. Switch modes by pushing a button.
If you are really starting from scratch and are out of touch with working
with bits and hex and shifting and all the little machine code tricks and
logic manipulations, I would suggest something quite different. Forget the
worries about hardware and compilers. Get a development kit from Rabbit
Semiconductor (ZWorld). It is a grown up Z80 at about 50 MHz (all those TI
calculators the schools use are Z80 -- the HP's are ARM7) but it doesn't
matter. They have a very nice mature C variant called Dynamic C and good
documentation and sample code and interrupt handling examples plus phone
support.
Yes the C is a little eccentric, but it is easier to get started with and
much easier to manage and use. The processor is not one of the currently
popular types, but that doesn't matter. You solve the same problems the same
way. There is a demand for experienced Rabbit programmers.
I used it once in a legacy 4MHz Z80 based plywood mill moisture controller
and bumped it to 48 MHz with one of ZWorld's modules, then did a few other
new jobs for the same company using the same hardware module. They were able
to get buying volume up and the modules were very inexpensive.
I had never touched a Z80 before the project, and aside from rejuvenating
S-100 systems, never will again. I would have used an ARM7 but the managers
were uncomfortable with the change and saw it as a risk. No big deal. It is
all ones and zeros.
In fact, I have an unopened development system if you want to buy one cheap.
I have been saving it for an occasion where I need to start from scratch with
no design and a laptop with no compilers, etc. (and no internet access if
need be) and get something going very quickly.
But I think you need a display so you can do the oscilloscope and similar
products.
-- Charlie Springer |
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Martin Griffith
Guest
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| Posted: Mon Nov 10, 2008 4:50 pm Post subject: Re: New to Embedded Software |
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On Sun, 09 Nov 2008 18:01:03 -0500, in comp.arch.embedded Rich Webb
<bbew.ar@mapson.nozirev.ten> wrote:
| Quote: | On Sun, 9 Nov 2008 12:30:55 -0800 (PST), Mike Silva
snarflemike@yahoo.com> wrote:
On Nov 9, 2:40 pm, Rich Webb <bbew...@mapson.nozirev.ten> wrote:
Sparkfun has a lot of dev boards and project ideas. A good "get your
feet wet" project could be to read the voltage at an A/D port and
display the results on a generic HD44780-based character LCD display
(these are widely available as inexpensive "surplus" if you're not
overly particular about the size of the display).
Funny you should suggest that. I just wired up a little comms test
unit with an AVR ATmega48, 3 slide pots and an LCD display, to send
out test commands and data over an RS485 line. The LCD display comes
from a batch I must have bought 20 years ago, and then forgot I had
them. It works just fine. The linear slide pots I just bought from
Mouser, OTOH, turn out to be audio taper. Oh well, not a big deal for
my purposes.
Yup. I agree with your earlier post that one of the first things to
learn is how to properly interact with a chip's interrupt structure. My
generic Hello, World for a new microcontroller (and, I suspect, many
other folks do this too) is to toggle a selected I/O pin at a 1 Hz rate
based on a timer interrupt. That gets most of the kinks out of the tool
chain and gives a basic understanding of the chip and its peripherals.
The HD44780 interface, though, is a good learning tool. RS, R/W* and E
do what? How does the crazy initialization work? Read the busy bit or do
fixed intervals? If the busy bit, what to do if the display is unplugged
and not-busy never occurs? Embedded development means it's embedded in
or with something else and understanding the incomplete, incorrect, or
contradictory documentation for that something else, and often building
a benchtop model of parts of it, is a big part of the game.
|
FYI
I'm just doing my first 44780 LCD/AVR project, and I found this
software
http://homepage.hispeed.ch/peterfleury/avr-software.html#libs
which seems quite comprehensive.
It compiles OK with WinAVR and Atmel Studio4
martin |
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Andrew Smallshaw
Guest
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| Posted: Mon Nov 10, 2008 7:22 pm Post subject: Re: New to Embedded Software |
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On 2008-11-09, Scott <ScottDSellers@googlemail.com> wrote:
| Quote: |
I am a 24 year old, Software Developer who has a 2.1 in BSc (Hons)
Software Development. I have been working solely on CRUD applications
during the 3 years I have been working and I have decided its time for
a change of direction in my career.
I would really like to begin working with Embedded/Real Time systems,
but my programming experience is with Delphi which is really a
programming language for RAD applications and I doubt it would be
suited to Embedded/Real Time systems.
I guess what I would really like to know is how to go about changing
the direction of my career, what programming languages do I need to
know, which operating systems is it best to use etc.
|
I see a lot of people are already talking about specific evaluation
boards which are good advice for the first foray into embedded
programming but for me that is missing an intermediate step. If
you only know Delphi then you are right - you need to learn more
about general software software development. What languages did
you learn at Uni? I was taught four - C, SML, Java and MIPS
assembler.
All those languages are fundamentally different in nature and
require you to think in different ways. One you are competent with
a range of languages such as these, switching to another language
is annoying and inconvenient, but nothing more than that because
you can put e.g. your SML hat on while getting to grips with Haskell
or whatever. Even my four doesn't cover all eventualities, since
e.g. stack based languages like Forth and PostScript are different
again, but I found I had sufficient background to easily get to
grips with PostScript at least, when I needed it.
The language of choice for most embedded work these days is C (not
C++) so I suggest learning that if you are not already competent
in C. Learn it well and I'd recommend a particular focus on
low-level implementation of various data structures, since that is
the biggest culture shock compared to higher level languages. A
knowledge of assembler is also useful background - it doesn't really
matter for what chip (although x86 is probably the wrong place to
start) and it needn't be particulary thorough - just enough that
you know what is happening under the hood.
Once you know C well, and roughly how C language structures correspond
to machine instruction sequences then you will have a much deeper
understanding and at a lower level. Then is the time to start
thinking about eval boards.
--
Andrew Smallshaw
andrews@sdf.lonestar.org |
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CBFalconer
Guest
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| Posted: Tue Nov 11, 2008 3:47 am Post subject: Re: New to Embedded Software |
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Rich Webb wrote:
| Quote: |
.... snip ...
The HD44780 interface, though, is a good learning tool. RS, R/W*
and E do what? How does the crazy initialization work? Read the
busy bit or do fixed intervals? If the busy bit, what to do if
the display is unplugged and not-busy never occurs? Embedded
development means it's embedded in or with something else and
understanding the incomplete, incorrect, or contradictory
documentation for that something else, and often building a
benchtop model of parts of it, is a big part of the game.
|
I assume you are talking about the display interface. You can't
use the busy signal until after initialization is complete, so you
will have to depend on local delays, such as counting
instructions. After initialization is complete you can use the
busy bit. Read the docs - it is quite straight forward.
--
[mail]: Chuck F (cbfalconer at maineline dot net)
[page]: <http://cbfalconer.home.att.net>
Try the download section. |
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CBFalconer
Guest
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| Posted: Tue Nov 11, 2008 3:50 am Post subject: Re: New to Embedded Software |
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Scott wrote:
| Quote: |
.... snip ...
I guess what I would really like to know is how to go about
changing the direction of my career, what programming languages
do I need to know, which operating systems is it best to use etc.
|
You need to know about hardware, C, assembly language, and most
important, be able to think. With luck you will get into systems
that use better languages, such as Pascal and Ada, but don't count
on it.
--
[mail]: Chuck F (cbfalconer at maineline dot net)
[page]: <http://cbfalconer.home.att.net>
Try the download section. |
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Rich Webb
Guest
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| Posted: Tue Nov 11, 2008 6:35 am Post subject: Re: New to Embedded Software |
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On Mon, 10 Nov 2008 16:47:11 -0500, CBFalconer <cbfalconer@yahoo.com>
wrote:
| Quote: | Rich Webb wrote:
... snip ...
The HD44780 interface, though, is a good learning tool. RS, R/W*
and E do what? How does the crazy initialization work? Read the
busy bit or do fixed intervals? If the busy bit, what to do if
the display is unplugged and not-busy never occurs? Embedded
development means it's embedded in or with something else and
understanding the incomplete, incorrect, or contradictory
documentation for that something else, and often building a
benchtop model of parts of it, is a big part of the game.
I assume you are talking about the display interface. You can't
use the busy signal until after initialization is complete, so you
will have to depend on local delays, such as counting
instructions. After initialization is complete you can use the
busy bit. Read the docs - it is quite straight forward.
|
Thanks, CB, but I'm well aware of the HD44780 init sequence, having done
one in C or assembler for several processor families.
The reason that I suggested that task to the guy wanting to get his feet
wet in embedded development is that the docs are probably NOT going to
be straightforward to somebody not accustomed to bit-twiddling,
setup/hold requirements, and the like. The "questions" above were some,
not all, of the things the OP might need to think about.
--
Rich Webb Norfolk, VA |
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Bocote
Guest
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| Posted: Tue Nov 11, 2008 6:36 am Post subject: Re: New to Embedded Software |
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Keil do good compilers etc and you can get limited evaluation versions.
Their Demo / prototyping boards are good value and there are lots of
example projects.
A few key things - multi threaded – you must master this. If you have a
motor that must be controlled then that must be controlled all the time,
and can't wait for user input, so user your Delphi to gain experience of
Multi Threaded applications and how to ensure they never give a wrong
result. This is fairly new on the desktop - but in the embedded world
everything is multi-threaded. In the embedded world crashes are not
permitted, so worry about how your multi threaded applications guarantee
that the data is never corrupted. Also how would you detect a failure and
gracefully recover from it.
Peter
Eden Electronics
The embedded system Specialists www.eden-electronics.co.uk |
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