AVR-Chat

Many thanks to your comprehensive post.  As a hobbist, never heard of GCC, or  WinAVR,  and now am curious to know more about them.

All mistakes in running code by my AVR simply solved by changing stack values in bascom environment settings, setting them to higher values.

As I always say "Very difficult questions sometimes have simple answers, and sometimes very simple questions have the most difficult answers."

Thanks again to those friend on this list who remind me of stack size, as well as those who had some points on noise reduction and capacitors.

Behrooz hariri


Reza <reza_agha@yahoo.com> wrote:                                  hi;
 
 I'm working with GCC but i tried using CodeVision
 also.
 but as you may know, there is a problem in design of
 AVR microcontrollers, they could not return from
 interrupts when stack lies in external sram. because
 of this some compilers like CodeVision (or maybe
 BasCom) use a hardware stack, and another data stack.
 
 but as I tested, these kind of dividing stack into two
 separated regions means the compiler prepared for the
 begineers or middle level programmers, not good ones.
 just for testing an algorithm.
 for example, in CodeVision AVR if you use a large
 table placed in flash, for example a font with a size
 of about 4KB in size, CodeVision never could generate
 a good code. ofcouse target code will not be run.
 
 maybe your problem solved using a powerfull compiler
 which I prefered as GCC (or WinAVR). some compilers
 seems to be a student work which released to be used
 by the others.
 
 if you checked the code the GCC I hope it works
 properly. as a suggestion I prefered following tools
 which I used frequently in different projects
 specially for automation control in a wide varity of
 projects. event with floating point operations and
 large amount of data:
 
 - CodeVision AVR (only for generating template program
 and configuring hardware).
 - WinAVR (from sourceforge or avrfreaks) for compiling
 the program.
 - Atmel AVRStudio 4.12 (or later) with Service Pack 2
 installed for debugging and using as an IDE.
 - Ponyprog2000 for programming and setting fuse bits.
 - or AvReal 1.25 serial downloader for serial
 programming when download speed is important, or using
 a command line program is a need.
 
 you should note if you are using floating point
 package, you must preserve at least 4KB of code in
 flash area, and somehow an amount of 128 or 256 bytes
 of SRAM storage for runtime support. in some cases you
 may have a bad result because of low speed in floating
 point calculations, which depend on the algorithm you
 may use, you may need a faster micro, using an
 external math co-processor (like the one in
 opencores.org) or simply convert your logic to use
 long integers (fixed point arithmetic) beside of using
 floating point (see PC Underground Book which uses a
 fixed point arithmetic for 3D matrix calculations).
 
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