Post by thread:[PICLIST] thesis programming help

I'm having trouble learning how to program this chip (PIC16F84 form microchip). It's for a simple application, digital pulse train input, 4Mhz clock, used to determine speed of incoming signal. Programmer is assembled...circuitry for device and sensor is fairly simple and almost complete. The only problem here is that I'm course 2 and I have no idea how to program at such a low level? where's "multiply?" where's "divide?" I've read enough to understand the architechure of the chip, the memory registers, and how data flows within it, but I can't for the life of me, decipher what these "btwscf" commands actually accomplish regarding my end goal! any suggestions? perhaps some similar sample programs with nicely detailed comments? i'd really appreciate it. thanks! Jonathan *************************************** Jonathan A. Coe Mechanical Engineering - Class of 2002 Massachusetts Institute of Technology 532 Beacon St. Boston, MA 02215 spam_OUTjcoeTakeThisOuTmit.edu *************************************** -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

So the gap you are running into is taking these small instructions and forming them into a larger more complex program. There are a few good PIC tutorials on the internet, one of which is found here: www.mstracey.btinternet.co.uk/pictutorial/picmain.htm (found using Google - there are others, you can check http://piclist.com for aid in finding them) This gap will be difficult for you to cross without a good understanding of binary logic and program flow. The instructions perform such little changes that it's much like building a castle from legos - it takes only three dozen different types of pieces, but how they are attached to each other (and the fact that you use hundreds of them) make the castle. There is, for instance, no multiply or divide. These are formed by a series of additions or subtractions, respectively, which the chip can do. If you are impatient, you can likely go to your local bookstore and get books on the pic. One which may be useful to you is "Programming and Customizing the PICMicro Microcontrollers" by Myke Predko - I found one in my local B&N. Another resource you have at your fingertips is MIT itself. There are many people there who use or have used PICs, and as the PIC matures there'll be more. I imagine you can do a homepage search on MIT servers and find some students there who could give you some first hand help. If you give us a good idea of what exactly you are trying to accomplish with your program, we can point you to projects which are similar. There are frequency counters, for instance, and engine tachometers which may suit your needs with only a little modification. -Adam Jonathan A. Coe wrote: {Quote hidden}>I'm having trouble learning how to program this chip (PIC16F84 form >microchip). It's for a simple application, digital pulse train input, 4Mhz >clock, used to determine speed of incoming signal. Programmer is >assembled...circuitry for device and sensor is fairly simple and almost >complete. The only problem here is that I'm course 2 and I have no idea how >to program at such a low level? where's "multiply?" where's "divide?" I've >read enough to understand the architechure of the chip, the memory >registers, and how data flows within it, but I can't for the life of me, >decipher what these "btwscf" commands actually accomplish regarding my end >goal! > >any suggestions? perhaps some similar sample programs with nicely detailed >comments? i'd really appreciate it. thanks! > >Jonathan > >*************************************** >Jonathan A. Coe >Mechanical Engineering - Class of 2002 >Massachusetts Institute of Technology >532 Beacon St. >Boston, MA 02215 >.....jcoeKILLspam@spam@mit.edu >*************************************** > >-- >http://www.piclist.com hint: The list server can filter out subtopics >(like ads or off topics) for you. See http://www.piclist.com/#topics > > > > > -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

On Thu, 18 Apr 2002 11:01:55 -0400, M. Adam Davis wrote: >So the gap you are running into is taking these small >instructions and forming them into a larger more complex >program. ..snip... {Quote hidden}>This gap will be difficult for you to cross without a good >understanding of binary logic and program flow. The >instructions perform such little changes that it's much like >building a castle from legos - it takes only three dozen >different types of pieces, but how they are attached to each >other (and the fact that you use hundreds of them) make the >castle. > >There is, for instance, no multiply or divide. These are formed >by a series of additions or subtractions, respectively, which >the chip can do. > >If you are impatient, you can likely go to your local bookstore >and get books on the pic. One which may be useful to you is >"Programming and Customizing the PICMicro Microcontrollers" by >Myke Predko - I found one in my local B&N. All very good ideas. But here's actually a great application for one of the inexpensive C compilers for the PIC like CCS PCM, which can be had for a very reasonable price of less than $100. Once the "newbie to PIC" programmer has the usual array of Microchip reference materials for his chip (datasheet and midrange reference guide) and maybe some PIC specific tutorials like Myke Predko's mentioned above, then the user can sit down and code some basic functions in C and study the resulting list file and code generated. The CCS compiler also has an extensive library for peripheral funtions, including software UARTS. That gives you lots of "pre-built" functions you can study and dissect in assembler. It's a great technique for understanding how, for instance, you make a multiply or divide function out of adds, subtracts, shifts, etc. By studying the code and PIC references, one can see how higher level constructs are formed from very simple instructions. Another often overlooked aspect of C compiler use (especially for low end chips like the PIC) is that you can always include as much or as little assembler code as you like. With most C compilers you can even code your entire application in assembler, if that suits you. Once a basic understanding of how the C compiler makes working code from all the PIC "bits and pieces", you can confidently program some large and complex tasks even on a chip as humble as the 16F84. Of course, I'd always suggest that any user work at fully understanding the chip at the assembler level. Being intimately familiar with all of the hardware registers and functions is a requirement for fully understanding your design. It's always a blend of hardware and software, one can't work correctly without good design practices in the other. Matt Pobursky Maximum Performance Systems -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics