Post by thread:To C or not to C for PICmicro

MPLABC compiles only upto 4 K of object code. Pailoor Gerhard Fiedler wrote: {Quote hidden}> At 08:43 02/03/99 -0600, Eric Oliver wrote: > >I am new to the PIC and micro-controllers in general. I am currently > > >working on a project of perhaps modest complexity ( very complicated > to me > ><g> ). My dilemma relates to the fact that I am just now getting my > feet > >wet with assembler but I have been using C on the PC platform for > years. I > >am tempted to use C as it would _greatly_ decrease my development > time. > > > >However, I realize that C can't be totally optimized to assembler and > I am > >concerned that the finished program could grow beyond the confines of > the > >PIC's program space. > > without any comments specific to your project, i would definitely use > c, > especially since you're already familiar with it. if you need to, you > can > always optimize the assembler code the compiler generates (one good > reason > to get one that does this!), which is a =lot= easier and faster than > writing it from scratch in assembler -- unless you're one of the > assembler > cracks. (and even when modifying quite a bit, a well written c > program, > included in the assembler file as comments, serves as a pretty decent > documentation -- just about what you'd have to write in your assembler > code > anyway.) > > ge -- Chip Technologies Microchip Design Consultant No. 70, 9th Main Road, Mathikere, Bangalore - 560 054. INDIA Tel : +91-80-3362807 Fax : +91-80-3369451 Email : spam_OUTchiptechTakeThisOuTvsnl.com Webpage : http://business.vsnl.com/chiptech

At 08:07 PM 2/3/99 -0700, you wrote: >MPLABC compiles only upto 4 K of object code. > >Pailoor MPLAB-C is a discontinued Microchip product. MPLAB-C17 has replaced it for the 17Cxx family and has no limitations on the size of object code. A fully functional demo version is available on the Microchip web site. Jim James Grosbach Development Systems Microchip Technology

James Grosbach wrote: > > At 08:07 PM 2/3/99 -0700, you wrote: > >MPLABC compiles only upto 4 K of object code. > > > >Pailoor > > MPLAB-C is a discontinued Microchip product. MPLAB-C17 has replaced it for > the 17Cxx family and has no limitations on the size of object code. A fully > functional demo version is available on the Microchip web site. > > Jim > > James Grosbach > Development Systems > Microchip Technology I agree! I did tests today, i got success for code greather than 4K Miguel

Can't afford the hi-tech compiler <g>. In fact, I'm having a hard time finding a compiler for the PIC17. I emailed CCS and they replied that they would be adding support for the PIC17 "real soon". I'm not sure _when_ that translates to. I have sent them another email to try to get a little more definite time frame. Thanks Eric {Original Message removed}

Russell, AFAIK, and I may be wrong, the 17X PIC instructions are a superset of the 16x PIC instructions. If so, could you use a 16X version C in the interim - this will give you access to 17X hardware features but not the more "efficient" (more CISC) instruction set? I wondered that, but the PIC17 uses a 16 bit instruction and the PIC16 uses a 14 bit instruction. Not knowing too much about microcontroller C compilers I wasn't sure if the code created by the CCS compiler could be used for the PIC17. Does the with of the instruction matter ? Maybe I could just use the compiler to create an intermediate ASM file and use MPASM on that file ?. Eric

Eric, It doesn't matter about the code _generated by_ the C compiler, if you eventually get a newer version of the compiler, as it will _generate_ new object code for the different PIC. In fact, you should be able to compile the same program for a whole bunch of different pics as long as you only address ports, timers, ADCs etc that exist on them all. If, on the other hand, you work with original or generated assembler, you can guarantee having to change a bunch of stuff for a new chip. If you can't wait for a new C compiler, then this is what you will have. > I wondered that, but the PIC17 uses a 16 bit instruction and the PIC16 uses > a 14 bit instruction. Not knowing too much about microcontroller C > compilers I wasn't sure if the code created by the CCS compiler could be > used for the PIC17. Does the with of the instruction matter ? Maybe I > could just use the compiler to create an intermediate ASM file and use > MPASM on that file ?. -- ______ ,----/ \----, Greg Nash .....gnashKILLspam@spam@namoicotton.com.au \ | | / Namoi Cotton, PO Box 58, Wee Waa 2388 \ \ o o / / work phone 02 6790 3011 fax 02 6790 3087 \/|\ /|\/ home phone 02 6793 5276 fax 02 6793 5319 | \ / | mobile 0417 253742 | \ \_| Private GregNashKILLspampastornet.net.au | |\_/| oooooooo http://www.geocities.com/Nashville/Opry/8450/

At 12:18 5/02/99 +1300, you wrote: >AFAIK, and I may be wrong, the 17X PIC instructions are a superset >of the 16x PIC instructions. Yes, but... >If so, could you use a 16X version C in the interim - this will give >you access to 17X hardware features but not the more "efficient" >(more CISC) instruction set? I no little about C compilers but I know enough about the 17C to know the above is just isn't practical. Some of the reasons you cannot use a 16C C compiler with 17Cxx parts are the differences in: Object code (16-bit Vs 14-bit) So you can compile to ASM but you still have: The I/O port addressing and I/O Banking (Killer) Different mode of bank switching (Killer) Different mnemonic encoding of the movf instruction. (Work around) Different mnemonics for RRF, RLF (Work around) Config word options (Work around) Some differences are easy to work around, others are not. There really are a lot of 16C/17C similarities but it is a case of "so near, yet so far." Jim >Russell McMahon > >{Original Message removed}

On Sun, Feb 07, 1999 at 09:41:21PM -0600, Eric Oliver wrote: > AFAIK, and I may be wrong, the 17X PIC instructions are a superset > of the 16x PIC instructions. Actually, no, they're not. Most PIC16 instructions have equivalents in the PIC17, but not all, and some that do behave differently (different flags set etc.) -- Clyde Smith-Stubbs | HI-TECH Software Email: .....clydeKILLspam.....htsoft.com | Phone Fax WWW: http://www.htsoft.com/ | USA: (408) 490 2885 (408) 490 2885 PGP: finger EraseMEclydespam_OUTTakeThisOuThtsoft.com | AUS: +61 7 3355 8333 +61 7 3355 8334 --------------------------------------------------------------------------- HI-TECH C: compiling the real world.