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I am using a Uno, GPS+SD card shield and LCD display and all runs fine with only 35% of memory used when not using the SD. When I add the SPI and SD Libraries for the SD card, combined they eat another 45% and I am getting a warning about reduced memory and the risk of unreliable performance. And, they are correct as sometimes writing to the SD doesn't work as expected.
The GPS/LCD work fine in their own Sketches. The SD/SPI work fine in their own Sketches. But when I combine the code I get the memory issues.
Since I only need to write to the SD card in CSV format, I am looking for a stripped down/SD/SPI combo that does only that as I can use a PC to read the data. I searched around and found a few possibles but they were all old and FAT16 only. I need to use FAT32 so I am currently stuck with SD/SPI.
I have ordered an Arduino Mega as it has 8M of memory so the problem should go away, but the original GPS is already set up in the dash of my truck and I would have to rebuild the brackets and project box for the Mega, so would like to just resolve the memory issue with the 4MB of the Uno. I am only going to use the Mega to make sure the full Sketch works OK and for 14-bucks, no big outlay for testing.
Can anyone help with a stripped down version of the SD/SPI combo as my code is tight enough until I add those Libraries.
Alternatively, you could get a stripped-down version of the GPS library. NeoGPS can be configured to be very small, both in terms of RAM and FLASH. It's also the fastest library out there. I wrote it because I had the same problem as you: combining multiple libraries in the smaller Arduinos revealed the bloat in all other GPS libraries: buffered copies of the sentences and data.
I've ripped open an old Pentium desktop. The main board is a Zida 5svx. I got to know from the manual (which i downloaded from the internet) the location of the ROM chip on the board, and took it out. It was mentioned in the manual that the chip was a Flash EEPROM.
Now, what I am interested in is this: Is there a way to erase the ROM and flash it with, say a C program to blink an LED (i know this might put you into a fit of laughter, but read on all the same), or control a motor?
I also want to know if I can construct a mega-sized micro-controller with the left-over Pentium, some MBs of RAM, and this ROM.
Any suggestions?
P.S: I know that such a uC will require appropriate power supply setup and things.
The key is in getting and deeply studying the manufacturer's datasheets for each device you remove and wish to reuse. I am supposing that since you asked the question that you did that you are not a professional electrical engineer - that's OK, but you will need to do hours, days, or weeks of study to truly understand the datasheets well enough to successfully reuse your motherboard chips because they are written for professional engineers with years of experience, and unfortunately they were not written to be understood by hobbyists. If you can succeed in acquiring and thoroughly understanding all of the datasheets (and the related user's guides as well for the more complex chips) then you have made it to the point where you might be able to start a custom design based on your recovered parts, on paper at least. In order to test your design and insure that each part of it is working will require at least an oscilloscope and volt meter - and the knowledge of how to use them. An understanding of basic electronics is essential, you will not succeed without it. Very good soldering/rework/assembly skills will be required as well if you hope to have your design truly work - you can do everything else right and it can still fail if your skills in this area are lacking. There is simply not enough time for me to advise you on everything you will need to know - but if you are motivated, dedicated, and you don't give up when setbacks and roadblocks occur (and trust me, they occur all too frequently for even the best engineers and best designs) - meaning that you are not easily frustrated when things don't work - then you have a chance at success. I wish you all the best, and try to have fun while doing it (important in case fun is all you ever get out of your project). :)
Are there any tips for reading source code samples from manufacturer of MCUs'.
I am a newbie for mcu programming, currently I have a MCU, datasheet and sample codes for them. But problem is sample codes are seems written for experienced users. Too many questions about why they initialized RS232, why they set 4th bit of port 1 and etc.,
Do you have a tips for reading or links where can I get info about how to read datasheets and sample codes of MCU?
I guess experience is the only answer I can give. Just like with programming in general, with time you acquire experience as well as learn buzz words and concepts. With microcontrollers you learn to read datasheets, schematics, etc. Learn about open drain, open collector, weak pull ups, etc. And for serial ports for some reason they are always overcomplicated. The hardest part with microcontrollers and the serial port is usually figuring out what to program to get the right clock divisors, some microcontroller serial ports are straight forward, others are overly complicated, some docs are good some docs are bad, etc.
Another answer is datasheets are always wrong. There are always gaps in the information that you have to hack to figure out. Do not write thousands of lines of code in a vaccuum using only a datasheet, write a small amount of code a few lines to a few dozen, test, and move on, you can get more lines written and debugged in a day when programming from a datasheet than the other path. The datasheets are often not written by the engineers that actually designed the hardware, sometimes it is a junior engineer or a non-engineer. Sometimes the information is simply wrong, sometimes the document is for a different but similar part than the one you have. If they provide software that actually does stuff it is sometimes (not always) more accurate than the datasheet (when I say datasheet assume the users manual, programmers reference manual, whatever the vendor calls the doc with the registers, addressses, and bit definitions for the hardware).
With time and experience you may find, if you take a wide enough view, that some vendors tend to do a better job at providing information to users, others do not, some bury the secrets in libraries, sometimes in binary form and not source. Sometimes the secrets are buried in compilers and other tools they provide (well that is back to apis and libraries). I tend to blacklist such companies, but sometimes you cant always. ARM for example does a very good job of providing the information. the problem is they have so many cores with a number of options each, that are very similar in nature (support the same instruction sets) that it can be difficult to sort through what the one processor you are using that moment does and does not from the docs. Atmel, something about atmel that is hard to put a finger on, the docs are generally well above par, but more than that something about atmel makes them popular with the customers. You will never see an arduino like following, culture, pick a word, with a microchip pic for example. There are a lot of pic followers but it is not like the atmel world (which was there well before the arduino thing happened).
Another note, you might not understand with a single example program and single datasheet the history of a product, there might be code that has been used for a number of chip generations, and there might for example be a bit that is required by an older chip or newer chip and to share the same code that bit is manipulated. that bit might make sense looking at one datasheet and no sense looking at another. this is where hacking comes, in try it without, see what happens. maybe study other parts in the family that this code is said to support it might make more sense.
google is your friend or whatever favorite search engine, find as much open source code and other items for the particular device or whatever. At this level hacking is required, I dont use that term in the bad sense, hacking in the sense that you have to try some of the bits documented in the datasheet, see if that actually works, if not then see what it does if possible, look at other source code and see from that if you can figure it out. Just like there is no perfect car that gets infinite miles per gallon, completely safe, lasts forever, and is inexpensive, there is no perfect chip with the perfect datasheet and sample code. If you want to work at this software/hardware level you have to get your hands dirty, have to not be afraid to let some smoke out of the chips (there is a finite amount of smoke in a chip if you let even a little bit out it wont work), etc.
If the reason you wont ask specifically about the mcu or register you are working with is because it is closed source products or behind an NDA then you probably have access to the company that makes that product and you should be able to get support from them. Usually better support than you would get from a company that you dont have to sign an NDA for. Not that open document, open source companies are bad, just that if the company you buy from is interested in you to the point of showing internally protected information they are interested enough to give you better access to the real engineers that made/know the product. If this is not the case and you are able to talk about it, dont be afraid to just post a question to SO about the register and bits you are wondering about.
Sample code and flow charts in the MCU datasheets are good starting point to initialize a specific peripheral (like RS232).
You just start from there, and track the bit information and what it does, in MCU datasheet.
Besides Arduino, what other ways are there to learn hardware programming in a hands-on way? Are there any nifty kits available, either a pre-assembled robot, that you can program to move a certain way, or do certain things, or anything similar to that?
Atmel AVR and the PIC both have experiment boards that you can use solder stuff on to, usually they have a couple of buttons and some lights pre-soldered to the area. This let's you program/flash the microprocessor and play with the output pins. You can either write the programs in assembly or C.
Parallax have a number of kits. They have two product lines suited for "playing around", Basic Stamp and something called Propeller. The former is a small microprocessor that runs programs written in Basic (a tad disgusting ;)) and the latter runs something called Spin or assembly (well after compilation obviously.)
I would go with either AVR or the PIC. I've done PIC but I've heard good things about AVR, they seem to ship with better software.
At first look Microsoft's VPL sounds good, but when it comes to actually LEARNING how hardware works it goes a LONG way to hide those details from you. As a matter of fact it is pretty much designed for people who don't program, and is distastful to someone who's actually written embedded software. IF you just want to make stuff happen and not delve into the details it's fine, but if you want to get down to the metal like programming the "Arduino" boards it's not for you.
If you're used to something like the Arduino then something like the PIC will be an easy transistion. SparcFun Electronics has all sorts of DIY type projects and hardware available. If you have a decent bookstore around your area, I would suggest looking for "Circuit Cellar" magazine. It has articles on a monthly basis with project for someone looking to get into hardware projects, everything from homebrew Software Defined Radio to FPGA based 3D graphics. (Raytracing actually) Usually the authors describe the project in an article and "WHY" they made the decisions they did, a description and schematics of the hardware and provide a link to source code.
Cypress Semiconductor has one of the most interesting embedded processors on the market and several high quality dev boards for sale. The PSoC includes the ability to not only configure the software, but also to "drop in" software configured hardware such Analog to digital converters, serial I/O, Digital to Analog and Various amps and filters. It's a REALLY cool concept, and the "touch sensor" capability of the PSoC were actually used in several models of the IPod.
One thing about programming these little micros is they don't have a lot between you and the hardware, you get to see how things really work. It doesn't matter whether you're talking about an 8-bit microcontroller or a quad-core Pentium programming hardware is largely the same concept. You write to a memory mapped register for some piece of hardware like a serial controller, and the hardware responds in someway. If you program a baudrate generator in a PIC or PC it's largely the same idea, you write a value that will be used as a division factor from a given clock to achive a given baudrate. The numbers and names maybe different, but the concepts is the same. On a PC you may have to map to the PCI address of the card, which adds a some complications, but if you looked underneath the OS you would see that that was done just by writing values to registers simalar to programming a PIC to use a different "Page" of memory. Is it worth learning an 8-bitter? Well, there are approximately $5 billion dollars in sales of the little 8-bit micros today with projection only showing growth in that market in the future. I saw one reference that state the average car has 25 Microcontrollers in it. That's not too bad.
I haven't played with it much, but the iRobot looks pretty cool.
The ability to simulate how your robot will work which some of the other answers mentioned is nice, but there's nothing like seeing a real-life robot do what you programmed it to do. That, to me, is what really makes robots fun and cool.
There's the .NET Micro Framework.
It's incredibly simple to use/setup and there's lots of hardware being made to target this framework.
You should take a look at Microsoft Robotics Developer Studio which supports many different kits.
I have always been curious about gumstix. It seems more professional than arduino, and it aims at the Linux programmer. I cannot give you a real suggestion, as I've never played with it, but I would definitely go with one of this toys if I had to do and learn some cool hardware programming.
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I'd like to learn how to program in Assembler. I've done a bit of assembly before (during my A-Level Computing course) but that was very definitely a simplified 'pseudo-assembler'. I've borrowed my Dad's old Z80 Assembler reference manual, and that seems quite interesting so if possible I'd like to have a go with Z80 assembler.
However, I don't have a Z80 processor to hand, and would like to do it on my PC (I have windows or linux so either is good). I've found various assemblers around on the internet, but I'm not particularly interested in assembling down to a hex file, I want to just be able to assemble it to something that some kind of simulator on the PC can run. Preferably this simulator would show me the contents of all the registers, memory locations etc, and let me step through instructions. I've found a few bits of software that suggest they might do this - but they either refuse to compile, or don't seem to work properly. Has anyone got any suggestions? If there are good simulator/IDE things available for another type of assembler then I could try that instead (assuming there is a good online reference manual available).
I've found a few bits of software that suggest they might do this - but they either
refuse to compile, or don't seem to work properly. Has anyone got any suggestions?
Write one. You're best off picking a nice, simple instruction set (Z80 should be perfect). I remember doing this as a first-year undergraduate exercise - I think we wrote the simulator in C++ and simulated 6800 assembly, but really any language/instruction set will do.
The idea of "learning assembly language" these days is to get the idea of how computers work at the lowest level, only a select few (compiler writers, etc.) have any real reason to actually be writing assembly code these days. Modern processors are stuffed full of features designed to be used by compilers to help optimise code for speed/concurrent execution/power consumption/etc., and trying to write assembly by hand for a modern processor would be a nightmare.
Don't fret about getting your application production-ready unless you want to - in all likelihood the bits of software you've found so far were written by people exactly like you who wanted to figure out how assembly works and wrote their own simulator, then realised how much work would be involved in getting it "production ready" so the general public could use it.
You might want to check out the open source 8085 simulator "GnuSim8085", it's specifically meant to be used for educational purposes, and it was in fact written by student while preparing for his exams. It runs on both, Linux and Windows.
WinApe is a good emulator of an Amstrad CPC. The Amstrad CPC was a Home Computer produced in the 80's. It used a Z80 as its CPU. Using the emulator you can display a lot of the internals while programming. It includes a debugger and a disassembler for Z80 code.
If Your are on windows 8085 Simulator is the best choice.
It user interface is excellent than any other simulator. Also this simulator provide live view of memory map very time(also while in the execution).
But this one does not support Windows 98 or lower for that you need to check other simulators like GNUSim8085.
MipSim is FREE
Main Features of MIPSim 2
Built-in code editor with features like syntax highlighting and folding
Display register and memory values in different representations (signed integer, unsigned integer, hexadecimal and ASCII)
Set the block size (full-word, half-word, byte) of the memory cells for easier examination of the memory values
Change values of registers and memory cells with a single click even during simulation and debugging
Realtime user-interface updating allows you to see how values of registers and memory cells change during execution
Built-in debugger with step-by-step instruction execution, instruction skipping and breakpoint features
Tools for inserting ASCII, UNICODE strings and integer values to memory for testing of your code
Tools for checking duplicate or missing labels and instruction parameters
Save computer state (values of all registers and memory cells) so that next time you run the simulator you can continue from where you left!
Set the simulation speed - low speeds are great to trace your code and to see how it behaves
Encode instructions - produce machine code in either binary or hexadecimal representation
Catch assembly time and runtime errors
Easier debugging with descriptive error messages
Multi-threaded design - MIPSim doesn't get stuck (hopefully ;) even if the assembly code executed is erroneous or contains infinite loops
MIPSim API - make your own programs that can read from and write to the registers and memory of MIPSim, great flexibility for powerful testing!
Aim higher! Try and get a simulator for a more powerful assembly language. Remember, Z80 and 808x were low-end processors with low-end and awkward instruction sets.
Something like VAX from DEC was regarded as the Rolls-Royce of instruction sets. And then there are crazy Risc instruction sets that do some really strange things. Maybe you can find definitions of those so that you can have a crack at implementing them.
You may be interested in this for a Z80 simulator, and I've had good experiences with WinAsm.
You might also consider learning x86 assembly language, which you could do using in-line assembler in Visual Studio - although it's a larger instruction set than Z80, you would have the advantage of being able to use much better tools than would be available for the Z80.
I've also just remembered that the Keil 8051 and Arm tools have a simulator in the IDE - there are size-restricted versions of these available for free download from www.keil.com
If you happen to already know .NET, then this may be of use:
http://www.viksoe.dk/code/asmil.htm
It's a little bit limited, and may only work with .NET 1.1, but you could atleast use a "modern" IDE for it, and there are plenty of docs around for it.
<%# page language="Asm80386" %>
<%
Str: DB "Testing...", 0
mov eax, -2
cmp eax, 2
jle Label1
xor eax, eax
Label1:
lea esi, Str
push esi
call "Response.Write(string)"
pop esi
%>
<br>EAX: <%= eax %>
Another option, if you want to go "hard core" is get something like FreeDOS and VMWare, and use that. I'm sure a garage sale (car boot sale? yard sale?) or second hand book shop would have a copy of Peter Norton's old DOS interrupts bible. :)
Personally, I learned x86 asm by using Turbo Pascal (which I think is now free from Borland?), which had the ability to embed assembly instructions inside a function. Made it easier to setup the app, and I could focus on the stuff I wanted to do. I later used MacVAX at Auckland Uni, which was ok, but the VAX is very much dead - you may as well learn x86 :)
SimpSim is definitely worth a look. It's Windows only, but the feature set is pretty decent:
Main memory and register display
Built-in editor with syntax highlighting
Run, step, and break functions
This wouldn't make any meaning to you now but just for people stopping by. This is the best assembly code simulator I have come across with. Truly worth it!
http://www.emu8086.com/
Take a look at Thomas Scherrer Z80 Emulators for a listing of potential emulators you could use.
I write z80 asm for the ZX Spectrum (still, I know :) ) and use SJasmPlus to link to a spectrum emulator file. Lots of of the better Spectrum emulators like Fuse and ZXSpin have built in editors as well for on the fly debugging and patching.
When I was in college we used PIC microprocessors. They are made by a company called Microchip. They also have a great IDE with a chip emulator/simulator that can allow you to do things without actually having the chips.
Why use an emulator?
Download MASM or NASM and write good old 80386 architecture. Plenty of online samples and learning tools.
Plenty of real-world reason to use assembler!
there is a simulator which is Visual6502 for teaching fundemental of microprocessor architecture. It has a editor, assembler, I/O operation and animation of how to work a microprocessor. I is available at the following link.
http://www.pcsistem.net/visual/index.htm