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I would like to learn something about embedded development. I think the best thing would be to buy hardware stuff and play with it but I don't know where to start and, if possible, I would like not to pay too much....
If you have experience in this field, which would be the best road to follow?
I assume you mean real embedded and not embedded linux or some other operating system thing.
All above are good, sparkfun.com is a GREAT resource for sub $50 cards. Dont buy the embed. The armmite pro is nice, trivial to bypass the high level canned package and load your own binaries (I have a web page on how to do it if interested).
Stellaris is good, the 811 is easy to brick so be careful, the 1968 eval board is not a bad one. The problem with the stellaris boards is almost all of their I/O is consuemed by on board peripherals. The good thing about the stellaris eval boards, based on what you are wanting to do is that all the I/O is consumed by on board peripherals. Lots of peripherals for you to learn how to write embedded code for.
You are going to eventually want a jtag wiggler, I recommend the amontec jtag-tiny, it will open the door to a number of the olimex boards from sparkfun. the sam7 and stm32 header boards are good ones as well.
the lillypad is a good starting place for arduino (sparkfun), same price as the arduino pro mini, but you dont have to do any soldering. get a lillypad and the little usb to serial thing that powers it and gives you serial access to program it. Just like the armmite pro I have a web page on how to erase the as-shipped flash and have a linux programmer that lets you load any binary you want not just ones limited to their sandbox.
avoid PIC and 8051 unless you are interested in a history lesson. the PIC32X, not sure my first one is in the mail, it is a MIPS 32 not a PIC core.
the ez430 msp430 board is a very good one, the msp430 has a very nice architecture, better than the avr.
You can get your feet wet in simulation as well. I have a thumb instruction set emulator, thumbulator.blogspot.com. Thumb is a subset of the arm instruction set and if you learn thumb then you can jump right into a stellaris board or stm32. My sim does not support thumb2, the thumb2 processors also support thumb, the transition to thumb2 from thumb is trivial.
avoid the stm32 primer boards, avoid the stm32 primer boards, avoid the mbed2 boards, avoid the mbed2 boards, avoid the lpcxpresso boards, avoid the lpcxpresso boards!!
I recently found a behavioral model of an arm in verilog that you can simulate your programs, have not played with it much. qemu-arm is probably easier, not a bad place to get your feet wet although it can be frustrating. Which is why I wrote my own.
ARMS own armulator is out there, in the gdb source release for example, easier than qemu-arm to use, but can be frustrating as well.
go to codesourcery for arm gcc tools. use mspgcc4.sf.net for msp430 tools. llvm is rapidly catching and passing gcc, if nothing else I expect it to replace gcc for the universal cross compiler tool. at the moment it is much more stable and portable than gcc when it comes to building for cross compiling (because it is always/only a cross compiler wherever you find or use it). the msp backend for llvm was an afternoon experiment for someone, sadly, I would really like to have that supported. If you use llvm, use clang not llvm-gcc.
If you want to get your feet wet, get a cheap evaluation board like Stellaris LM3S811 Evaluation Kit (EK-LM3S811) which is $50 at Digi-Key then download CodeSourcery G++ which provides free command line tools or the IAR Kickstart Edition which allows you up to 32KB of code.
I would suggest starting up with MSP430. The MSP430 launchpad is quiet cheap. Alternatively, you could start up with the Stellaris (ARM Cortex M3) Boards. You can use the already provided libraries first to start developing apps rite away and then start writing your code for configuring and getting things done by referring the data sheet.You also get example codes, relevant documents and Keil 32K limited evaluation version. If you want to do things write from scratch, then get an ARM based board with IO breakout headers and start working. Lot of them are available from vendors like Olimex. One word of caution ARM is difficult to start with if you are working from scratch with little or no idea about embedded. So if you are looking for something easier go for AVR or 8051, but 8051 core is too old. So, Stellaris would be a good option in my opinion with their already available driver libs and codes.
Well, depending how much money you want to spend, and how much development expertise you have, you could either get an Arduino (arduino.cc) or a FEZ Domino (C# .NET) (tinyclr.com). Both are premade MCUs, with all the tools you need to start developing out of the box.
The Arduino is going to be very simplistic, but probably better for a beginner. The FEZ is a little harder to work with, but FAR more capable. Both have the same physical pinout, so you can use "shields" between them
I would recommend a kickstart kit from iar systems. They're fairly complete and work out of the box.
http://www.iar.com/website1/1.0.1.0/16/1/
As a hobby project to keep myself out of trouble, I'd like to build a little programmer timer device. It will basically accept a program which is a list of times and then count down from each time.
I'd like to use a C or Java micro controller. I have used BASIC in the past to make a little autonomous robot, so this time around I'd like something different.
What micro controller and display would you recommend? I am looking to keep it simple, so the program would be loaded into memory via computer (serial is ok, but USB would make it easier)
Just use a PIC like 16F84 or 16F877 for this. It is more than enough.
As LCD use a 16 x 2 LCD. It is easy to use + will give a nice look to your project.
LCD
The language is not a matter. You can use PIC C, Micro C or any thing you like. The LCD's interface is really easy to drive.
As other components you will just need the crystal and 2 capacitors as oscillator + pull up resister. The rest of the components depend on the input method that you are going to use to set the times.
If you are using a computer to load the list then you will need additional circuit to change the protocols. Use MAX 232 to do that. If you want to use USB, you need to go ahead and use a PIC with USB support. (18F series)
(source: sodoityourself.com)
This is a set of nice tutorials you can use. You can purchase the products from them as well. I purchased once from them.
I would go with the msp430. An ez430 is $20 and you can get them at digikey or from ti directly, then sets of 3 microcontroller boards for $10 after that. llvm and gcc (and binutils) compiler support. Super simple to program, extremely small and extremely low power.
There are many ways to do this, and a number of people have already given pretty good suggestions AVR or PIC are good starting points for a microcontroller to work with that doesn't require too much in the way of complicated setup (hardware & software) or expense (these micros are very cheap). Honestly I'm somewhat surprised that nobody has mentioned Arduino here yet, which happens to have the advantage of being pretty easy to get started with, provides a USB connection (USB->Serial, really), and if you don't like the board that the ATMega MCU is plugged into, you can later plug it in wherever you might want it. Also, while the provided programming environment provides some high level tools to easily protype things you're still free to tweak the registers on the device and write any C code you might want to run on it.
As for an LCD display to use, I would recommend looking for anything that's either based on an HD44780 or emulates the behavior of one. These will typically use a set of parallel lines for talking to the display, but there are tons code examples for interfacing with these. In Arduino's case, you can find examples for this type of display, and many others, on the Arduino Playground here: http://www.arduino.cc/playground/Code/LCD
As far as a clock is concerned, you can use the built-in clock that many 8-bit micros these days provide, although they're not always ideal in terms of precision. You can find an example for Arduino on doing this sort of thing here: http://www.arduino.cc/playground/Code/DateTime. If you want something that might be a little more precise you can get a DS1307 (Arduino example: http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1191209057/0).
I don't necessarily mean to ram you towards an Arduino, since there are a huge number of ways to do this sort of thing. Lately I've been working with 32-bit ARM micros (don't do that route first, much steeper learning curve, but they have many benefits) and I might use something in that ecosystem these days, but the Arduino is easy to recommend because it's relatively inexpensive, there's a large community of people out there using it, and chances are you can find a code example for at least part of what you're trying to do. When you need something that has more horsepower, configuration options, or RAM, there are options out there.
Here are a few places where you can find some neat hardware (Arduino-related and otherwise) for projects like the one you're describing:
SparkFun Electronics
Adafruit Industries
DigiKey (this is a general electronics supplier, they have a bit of everything)
There are certainly tons more, though :-)
I agree with the other answers about using a PIC.
The PIC16F family does have C compilers available, though it is not ideally suited for C code. If performance is an issue, the 18F family would be better.
Note also that some PICs have internal RC oscillators. These aren't as precise as external crystals, but if that doesn't matter, then it's one less component (or three with its capacitors) to put on your board.
Microchip's ICD PIC programmer (for downloading and debugging your PIC software) plugs into the PC's USB port, and connects to the microcontroller via an RJ-11 connector.
Separately, if you want the software on the microcontroller to send data to the PC (e.g. to print messages in HyperTerminal), you can use a USB to RS232/TTL converter. One end goes into your PC's USB socket, and appears as a normal serial port; the other comes out to 5 V or 3.3 V signals that can be connected directly to your processor's UART, with no level-shifting required.
We've used TTL-232R-3V3 from FDTI Chip, which works perfectly for this kind of application.
There are several ways to do this, and there is a lot of information on the net. If you are going to use micro controllers then you might need to invest in some programming equipment for them. This won't cost you much though.
Simplest way is to use the sinus wave from the power grid. In Europe the AC power has a frequency of 50Hz, and you can use that as the basis for your clock signal.
I've used Atmel's ATtiny and ATmega, which are great for programming simple and advanced projects. You can program it with C or Assembly, there are lots of great projects for it on the net, and the programmers available are very cheap.
Here is a project I found by Googling AVR 7 segment clock.
A second vote for PIC. Also, I recommend the magazine Circuit Cellar Ink. Some technical bookstores carry it, or you can subscribe: http://www.circellar.com/
PIC series will be good, since you are creating a timer, I recommend C or Assembly (Assembly is good), and use MPLAB as the development environment. You can check how accurate your timer with 'Stopwatch' in MPLAB. Also PIC16F877 has built in Hardware Serial Port. Also PIC16F628 has a built in Hardware serial port. But PIC16F877 has more ports. For more accurate timers, using higher frequency oscillators is recommended.
How can I make my own microcontroller? I've done some work using GAL chips and programmed a chip to do simple commands such as add, load, move, xor, and output, but I'd like to do something more like a real microcontroller.
How can I go about doing this? I've read a little bit about FPGA and CPLD, but not very much, and so was looking for some advice on what to get and how to start developing on it.
Look here for a good wiki book. I had some coursework I wrote when I was teaching Electronic Eng, but I couldn't find it around. When I was teaching, most of the students were happy to use the schematic capture tools in the Xilinx Foundation package. They've moved onto ISE and WebPACK now. You can download the WebPack for free, which is useful, and it has schematic capture and simulation in it.
If you really want to shine, learn VHDL or Verilog (VHDL seems to be more common where I've worked, but that is only a small smattering of places) and code the design rather than enter it through the GUI.
If you know ANYTHING at all about digital logic design (and some HDL) I rekon you can have a somewhat functional 8-bit microprocessor simulating in VHDL in about 2 days. You're not going to build anything blazingly fast or enormously powerful in that time but it's a good starting point to grow from. If you have to learn about digital design, factor in a couple of days to learn how the tools work and simulate some basic logic circuits before moving onto the uP design.
Start learning the basics of digital systems, and how to build a binary adder. Move on to building an ALU to handle addition, subtraction, and, or, xor, etc and then a sequencer to read opcodes from RAM and supply them to the execution unit.
You can get fancy with instruction set design, but I'd recommend starting out REALLY simple until you have your head around whats going on, then throw it out and start again with something more complex.
Once you have the design simulating nicely you can gauge its complexity and purchase a device to suit. You should look at a development system for the device family you've chosen. Pick a device bigger than what you need for development because it's nice to be able to add extra instrumentation to debug it when it's running, and you almost certainly won't have optimized your design in the early stages of getting it on the device.
EDIT: Colin Mackenzie has a good tutorial about uC design and some FPGA boards as well as a bit of other stuff.
You may want to have a look around OpenCores.org, a "forge" site for open source IP core development. Also, consider getting yourself a development board like one of these to play around with.
Much of the tools ecosystem revolves around VHDL, although Avalda is working on tools to compile F# for FPGAs.
I saw a textbook once that stepped through building a machine from TTL chips. This had the same instruction set as a PDP-8, which is very - and I mean very - simple, so the actual machine architecture is easy to implement in this way.
The PDP-8 FAQ mentions a book: "The Art of Digital Design," second edition, by Franklin Prosser and David Winkel (Prentice-Hall, 1987, ISBN 0-13-046780-4). It also mentions people implementing it in FPGA's.
Given the extreme simplicity of this CPU architecture and availability of PDP-8 code or reference implementations it might be a good starting point to warm up with.
Alternatively, an acquaintance of mine implemented a thumb (cut down ARM) on a FPGA as a university project run by one Steve Furber (a prominent Acorn alumnus). Given that this could be compressed into a format small enough for a university project it might also be a good start.
To play with soft-core microprocessors, I like the Spartan 3 Starter Board from Digilent just because it has 1M of static RAM. SDRAM and DDR RAM are harder to get going, you know.
The leds, switches and a simple serial interface are a plus to debug and communicate.
As someone already pointed out, OpenCores.org is a good place to find working examples. I used the Plasma uC to write some papers while on university.
A microcontroller can be as simple as a ROM (instruction*2^x + (clock phase) is the address, outputs are the control signals, and you're good to go). Or it can be a complex harry beast with three arms and branch prediction support hardware.
Can you give more details about your aspirations?
After searching some very helpful links by all of you, I came across this Wikiversity course.
One of the first sentences is, "Have you ever thought to build your own microprocessor?"
Xilinx has a MicroBlaze and a PicoBlaze soft controller for its FPGAs. The latter is free, while, IIRC, the Microblaze is to be paid for.
As its name suggests the PicoBlaze is a small processor, which has its limitations, but OTOH is compact enough to run on a CPLD. Anyway a nice processor to get you started.
Pablo Bleyer has a PicoBlaze-compatible PacoBlaze. PacoBlaze was written in Verilog (which, like Adam said, less common than VHDL).
You need a big fpga for a little mcu.
You need a fpga with the correct hardware blocks if you need things like AD.
You need a soft core to put into the fpga.
But how about to just play around with a normal MCU before this project,
so you kind of know where you are going? How about some AVR:s from Atmel.
You can get free samples of pic micro controllers at this site. Last I knew, you don't even have to pay shipping.
http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=64
I'm a C# developer, I'm interested in embedded development for chips like MSP430. Please suggest some tools and tutorials.
Mono framework is very powerful and customizable, mono specific examples will be more helpful.
Mono requires a 32 bit system, it is not going to work on 16-bit systems.
There is currently no full mono support for the MSP430.
Mono doesn't run in a vacuum - you will need to make a program that exposes the microcontroller functionality to Mono, then link to Mono and program the entire thing on the microcontroller. This program will have to provide some functionality to Mono that is normally provided by an operating system.
The paged igorgue linked to gives you a good starting point for this process: http://www.mono-project.com/Embedding%5FMono
I don't know what the requirements of the Mono VM are, though. It may be easy to compile and use, or you may have to write a lot of supporting code, or dig deep into mono to disable code you won't be using, or can't support on the chosen microcontroller.
Further, Mono isn't gargantuan, but it's complex and designed with larger 32 bit processors in mind. It may or may not fit onto the relatively limited 16 bit MSP430.
However, the MSP430 does have a GCC port, so you don't have to port the mono code to a new compiler, which should make your job easier.
Good luck, and please let us know what you decide to do, and how it works out!
-Adam
The tools to use Mono on an MSP430 just aren't available. Drop all the C# and use C/C++ instead.
MSP devices usually have 8 to 256KB Flash and 256 bytes (!) to 16kBytes of RAM.
Using C# or even c++ is really not an option. Also, complex frameworks are a no-go.
If you really want to start with MSP430 (which are powerful, fast and extremely low-power processors for their area of use), you should look for the MSPGCC toolchain.
http://mspgcc.sourceforge.net/
It contains compiler (GCC3.22 based) along with all necessary tools (make, JTAG programmer etc.). Most MSP processors are supported with code optimisation and support of internal hardware such as the hardware multiplier.
All you need is an editor (yopu can use Eclipse, UltraEdit or even the normal Notepad) and some knowledge about writing a simple makefile.
And you should prepare to write tight code (especially in terms of ram usage).
I think that Netduino can be of some interest for you.
Visit their web site at http://netduino.com/.
It's opensource hardware (like Arduino, http://www.arduino.cc/).
It runs .NET Micro Framework (http://www.microsoft.com/en-us/netmf/default.aspx), the breed oriented to embedded development.
Regards,
Giacomo
I would like to create/start a simulator for the following microcontroller board: http://www.sparkfun.com/commerce/product_info.php?products_id=707#
The firmware is written in assembly so I'm looking for some pointers on how one would go about simulating the inputs that the hardware would receive and then the simulator would respond to the outputs from the firmware. (which would also require running the firmware in the simulated environment).
Any pointers on how to start?
Thanks
Chris
Writing a whole emulator is going to be a real challenge. I've attempted to write an ARM emulator before, and let me tell you, it's not a small project. You're going to either have to emulate the entire CPU core, or find one that's already written.
You'll also need to figure out how all the IO works. There may be docs from sparkfun about that board, but you'll need to write a memory manager if it uses MMIO, etc.
The concept of an emulator isn't that far away from an interpreter, really. You need to interpret the firmware code, and basically follow along with the instructions.
I would recommend a good interactive debugger instead of tackling an emulator. The chances of destroying the hardware is low, but really, would you rather buy a new board or spend 9 months writing something that won't implement the entire system?
It's likely that the PIC 18F2520 already has an emulator core written for it, but you'll need to delve into all the hardware specs to see how all the IO is mapped still. If you're feeling up to it, it would be a good project, but I would consider just using a remote debugger instead.
You'll have to write a PIC simulator and then emulate the IO functionality of the ports.
To be honest, it looks like its designed as a dev kit - I wouldn't worry about your code destroying the device if you take care. Unless this a runner-up for an enterprise package, I would seriously question the ROI on writing a sim.
Is there a particular reason to make an emulator/simulator, vs. just using the real thing?
The board is inexpensive; Microchip now has the RealICE debugger which is quite a bit more responsive than the old ICD2 "hockey puck".
Microchip's MPLAB already has a built-in simulator. It won't simulate the whole board for you, but it will handle the 18F2520. You can sort of use input test vectors & log output files, I've done this before with a different Microchip IC and it was doable but kinda cumbersome. I would suggest you take the unit-testing approach and modularize the way you do things; figure out your test inputs and expected outputs for a manageable piece of the system.
It's likely that the PIC 18F2520 already has an emulator core written for it,
An open source, cross-platform simulator for microchip/PICs is available under the name of "gpsim".
It's extremely unlikely that a bug in your code could damage the physical circuitry. If that's possible, then it is either a bug in the board design or it should be very clearly documented.
If I may offer you a suggestion from many years of experience working with these devices: don't program them in assembly. You will go insane. Use C or BASIC or some higher-level language. Microchip produces a C compiler for most of their chips (dunno about this one), and other companies produce them as well.
If you insist on using an emulator, I'm pretty sure Microchip makes an emulator for nearly every one of their microcontrollers (at least one from each product line, which would probably be good enough). These emulators are not always cheap, and I'm unsure of their ability to accept complex external input.
If you still want to try writing your own, I think you'll find that emulating the PIC itself will be fairly straightforward -- the format of all the opcodes is well documented, as is the memory architecture, etc. It's going to be emulating the other devices on the board and the interconnections between them that will kill you. You might want to look into coding the interconnections between the components using a VHDL tool that will allow you to create custom simulations for the different components.
Isn't this a hardware-in-the-loop simulator problem? (e.g. http://www.embedded.com/15201692 )