Post by thread:[PIC] assembler directive question

hi, i'm not very experienced with assembler directives, so i don't know if this is achievable. i have an asm program that has many subroutines, each lights a different letter on a 5x7 LED display. In my main program, i call whatever subroutine I want, for example, to display "HELLO" : start call HHH ; light up H call Pause; call EEE; light up E call Pause; call LLL; light up L call Pause; call LLL; light up L call Pause; call OOO; light up O call Pause; goto start i have programmed the whole alphabet and other characters, but they do not all fit on the PIC. what i want to do is program only the ones that get called, and have the assembler ignore the rest. i have been looking at #DEFINE, IFDEF, and IF statements, but i can't seem to figure this out. can somebody point me in the right direction? i'm using MPLAB. -- Scott Larson 3201 S. State. St. box 2561 Chicago, Il, 60616 619-400-9775 http://goldscott.com

On October 16, 2005 10:52 pm, scott larson wrote: {Quote hidden}> hi, > i'm not very experienced with assembler directives, so i don't know > if this is achievable. > i have an asm program that has many subroutines, each lights a > different letter on a 5x7 LED display. In my main program, i call > whatever subroutine I want, for example, to display "HELLO" : > start > call HHH ; light up H > call Pause; > call EEE; light up E > call Pause; > call LLL; light up L > call Pause; > call LLL; light up L > call Pause; > call OOO; light up O > call Pause; > goto start > i have programmed the whole alphabet and other characters, but they > do not all fit on the PIC. > what i want to do is program only the ones that get called, and have > the assembler ignore the rest. > i have been looking at #DEFINE, IFDEF, and IF statements, but i > can't seem to figure this out. > can somebody point me in the right direction? > i'm using MPLAB. create a small asm program with this in it: #define EXAMPLE 1 #ifdef EXAMPLE #define HI 1 #define LO 0 #else #define HI 0 #define LO 1 #endif #ifndef EXAMPLE #define X 1 #define Y 2 #else #define X 3 #define Y 4 #endif in the code section, insert this: retlw HI retlw LO retlw X retlw Y you can also insert this in the code section: #ifdef EXAMPLE movlw 5 movlw HI #else movlw 10 movlw HI+Y #endif try the above with and without "#define EXAMPLE"

Which PIC are you not able in include the whole alphabet? I've never run out of code space... ever! scott larson wrote: {Quote hidden}>hi, >i'm not very experienced with assembler directives, so i don't know if this >is achievable. >i have an asm program that has many subroutines, each lights a different >letter on a 5x7 LED display. In my main program, i call whatever subroutine >I want, for example, to display "HELLO" : > start >call HHH ; light up H >call Pause; >call EEE; light up E >call Pause; >call LLL; light up L >call Pause; > call LLL; light up L >call Pause; >call OOO; light up O >call Pause; >goto start > i have programmed the whole alphabet and other characters, but they do not >all fit on the PIC. >what i want to do is program only the ones that get called, and have the >assembler ignore the rest. > i have been looking at #DEFINE, IFDEF, and IF statements, but i can't seem >to figure this out. > can somebody point me in the right direction? > i'm using MPLAB. > >-- >Scott Larson >3201 S. State. St. box 2561 >Chicago, Il, 60616 >619-400-9775 >http://goldscott.com > > -- * | __O Thomas C. Sefranek spam_OUTWA1RHPTakeThisOuTARRL.net |_-\<,_ Amateur Radio Operator: WA1RHP (*)/ (*) Bicycle mobile on 145.41, 448.625 MHz hamradio.cmcorp.com/inventory/Inventory.html http://www.harvardrepeater.org

scott larson wrote: > i have an asm program that has many subroutines, each lights a different > letter on a 5x7 LED display. In my main program, i call whatever > subroutine I want, for example, to display "HELLO" : > start > call HHH ; light up H > call Pause; > call EEE; light up E > call Pause; > call LLL; light up L > call Pause; > call LLL; light up L > call Pause; > call OOO; light up O > call Pause; > goto start What assembler are you using? MPASM would have barfed on this code because of opcode mnemonics in column 1. You're going to get a lot more answers here if you stick to the standard tools. At the very least you should point out that you're using a non-standard tool. My answers below related to MPASM. > i have programmed the whole alphabet and other characters, but they do > not all fit on the PIC. Not surprising doing it this way. I would make a single subroutine that you pass the character to. This does a table lookup and then displays the result. If you stick to printable ASCII characters, then you only need codes from 32 to 127 at most. That table and the code to use it only exist once. You could even write a subroutine that takes a pointer to a string in program memory and displays that. This would be layered on the previous subroutine that displays one character. > what i want to do is program only the ones that get called, and have the > assembler ignore the rest. It would be a bit tricky to do this with the assembler. You could do it for references from one module only. The best way is to put each subroutine in its own module, make a library of them all, then let the linker pick what it needs. I do this routinely with all my code except the startup module that contains the reset vector. That way I can write debug routines that can stay as part of the project but don't end up in the PIC unless they are called. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com

Tom Sefranek wrote: > Which PIC are you not able in include the whole alphabet? > I've never run out of code space... ever! But Tom, didn't you start with the 18C252 (before it was ready) and then move up from there? There's a whole world of "little" PICs out there. You're doing very low volume high cost stuff, but when it's the other way around the cost of a PIC matters. Most of my PIC projects are either pushing cycles, RAM, or code space, although usually not all those together. I do have this one 16F630 project where everything is tight, but this is a high volume product and the customer absolutely doesn't want a more expensive PIC in there. The feature set is basically defined by what I can cram into the PIC. Personally I think this is the fun part. It's not so hard to design something when plenty of resources are available. The real challenge is optimising capability together with cost. That's why I sometimes say our motto is "20 pounds of firmware in a 10 pound PIC". ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com

On 17 Oct 2005, at 12:43, Olin Lathrop wrote: > I do have this one 16F630 project where everything is tight, but > this is a > high volume product and the customer absolutely doesn't want a more > expensive PIC in there. The feature set is basically defined by > what I can > cram into the PIC. Personally I think this is the fun part. It's > not so > hard to design something when plenty of resources are available. > The real > challenge is optimising capability together with cost. That's why I > sometimes say our motto is "20 pounds of firmware in a 10 pound PIC". "An engineer is someone who can do for $1 what any fool can do for $10" -- Andy Armstrong, hexten.net

2005/10/17, Tom Sefranek <.....tcsKILLspam@spam@cmcorp.com>: > Which PIC are you not able in include the whole alphabet? > I've never run out of code space... ever! Just to explain this: supposing an alphabet of 40 characters, a reasonable estimate for a 5*7 display would be 40*5=200 program memory words. Usually those are available (I ran out of program memory several times already, so I wouldn't say "ever") and if not, there are some clever compressions you can do to reduce it further (let me know if you need those). If you code each letter as an actual subroutine, you would consume a lot more space. A better design would be to use a table (Microchip AN556, I believe) and retrieve the five bytes needed for a character and output them accordingly. An example routine of the concept, which will probably not compile (I just wrote it in this Email): ; This function assumes the character to be in "Character5x7" ; and the desired line to be in "Line5x7" Get5x7VerticalLine banksel Character5x7 ; Make sure we talk about the right variable clrf STATUS,C ; Start multiplication by five rlf Character5x7,w ; Multiply by two movwf GVLine ; Store clrf STATUS,C ; Continue multiplication by five rlf GVLine,f ; Multiply by four movf Character5x7,w ; Continue multiplication by five addwf GVLine,f ; *2*2+1=5 movf Line5x7,f ; Add the desired line addwf GVLine,w ; W now contains location in memory pagesel CharacterTable ; Point to the character table movwf PCL ; Jump into the table ; This is the character table. Make sure that it starts on a 256 aligned ; boundary in memory. CharacterTable dt 127,9,9,9,127 ; A dt 127,73,73,79,120 ; B ... Note that I used "pagesel" here to select the upper bits of PCLATH used for table jumps, I'm not sure if pagesel actually does this. If not, you would have to manually set these bits. A similar construction could be used to send the actual message, saving space there too. Greetings, Maarten Hofman.

Close, it was the PIC18C452. I have NEVER been even close to out of code space. It takes a HLL Compiler to do that. Now RAM and cycles on the other hand... Olin Lathrop wrote: {Quote hidden}> Tom Sefranek wrote: > >> Which PIC are you not able in include the whole alphabet? >> I've never run out of code space... ever! > > > But Tom, didn't you start with the 18C252 (before it was ready) and then > move up from there? There's a whole world of "little" PICs out there. > You're doing very low volume high cost stuff, but when it's the other way > around the cost of a PIC matters. Most of my PIC projects are either > pushing cycles, RAM, or code space, although usually not all those > together. > > I do have this one 16F630 project where everything is tight, but this > is a > high volume product and the customer absolutely doesn't want a more > expensive PIC in there. The feature set is basically defined by what > I can > cram into the PIC. Personally I think this is the fun part. It's not so > hard to design something when plenty of resources are available. The > real > challenge is optimising capability together with cost. That's why I > sometimes say our motto is "20 pounds of firmware in a 10 pound PIC". > > > ***************************************************************** > Embed Inc, embedded system specialists in Littleton Massachusetts > (978) 742-9014, http://www.embedinc.com -- * | __O Thomas C. Sefranek WA1RHPKILLspamARRL.net |_-\<,_ Amateur Radio Operator: WA1RHP (*)/ (*) Bicycle mobile on 145.41, 448.625 MHz hamradio.cmcorp.com/inventory/Inventory.html http://www.harvardrepeater.org

I run out of code space all the time! On 10/17/05, Tom Sefranek <.....tcsKILLspam.....cmcorp.com> wrote: {Quote hidden}> > Which PIC are you not able in include the whole alphabet? > I've never run out of code space... ever! > > scott larson wrote: > > >hi, > >i'm not very experienced with assembler directives, so i don't know if > this > >is achievable. > >i have an asm program that has many subroutines, each lights a different > >letter on a 5x7 LED display. In my main program, i call whatever > subroutine > >I want, for example, to display "HELLO" : > > start > >call HHH ; light up H > >call Pause; > >call EEE; light up E > >call Pause; > >call LLL; light up L > >call Pause; > > call LLL; light up L > >call Pause; > >call OOO; light up O > >call Pause; > >goto start > > i have programmed the whole alphabet and other characters, but they do > not > >all fit on the PIC. > >what i want to do is program only the ones that get called, and have the > >assembler ignore the rest. > > i have been looking at #DEFINE, IFDEF, and IF statements, but i can't > seem > >to figure this out. > > can somebody point me in the right direction? > > i'm using MPLAB. > > > >-- > >Scott Larson > >3201 S. State. St. box 2561 > >Chicago, Il, 60616 > >619-400-9775 > >http://goldscott.com > > > > > > -- > * > | __O Thomas C. Sefranek EraseMEWA1RHPspam_OUTTakeThisOuTARRL.net > |_-\<,_ Amateur Radio Operator: WA1RHP > (*)/ (*) Bicycle mobile on 145.41, 448.625 MHz > > hamradio.cmcorp.com/inventory/Inventory.html > http://www.harvardrepeater.org > > >

Scott, Can you show us one or two of your subroutines? It sounds like you might have a lot of redundant code. I wonder why you don't have a single subroutine, the character bit map info might be drawn from a table. A possible way to include only wanted routines is to disable ALL of them with "remark" prefixes and then let them in one by one till you don't get a compilation error. >> scott larson wrote: >> >> >hi, >> >i'm not very experienced with assembler directives, so i don't know if >> this >> >is achievable. >> >i have an asm program that has many subroutines, each lights a different >> >letter on a 5x7 LED display. In my main program, i call whatever >> subroutine >> >I want, for example, to display "HELLO" : >> > start >> >call HHH ; light up H >> >call Pause; >> >call EEE; light up E >> >call Pause; >> >call LLL; light up L >> >call Pause; >> > call LLL; light up L >> >call Pause; >> >call OOO; light up O >> >call Pause; >> >goto start >> > i have programmed the whole alphabet and other characters, but they do >> not >> >all fit on the PIC. >> >what i want to do is program only the ones that get called, and have the >> >assembler ignore the rest. >> > i have been looking at #DEFINE, IFDEF, and IF statements, but i can't >> seem >> >to figure this out. >> > can somebody point me in the right direction? >> > i'm using MPLAB.

my code is very redundant. i have not learned about tables yet, but clearly that is the next step i must take. maarten, bill, and olin have made me realize what i need to do. each letter looks some thing like this: ;**** AAA Light up letter A ; ; O ; O O ; O O ; O O ; OOOOO ; O O ; O O AAA ;****Set up CYCLE counter movlw CYCLES ;change this value to change the length of time the letter is displayed, about 0x80 movwf CYCLE ;register to move CYCLES into AAA1 ;Column 1 movlw b'11101111' ;low column 1 (for common cathode display) movwf PORTA movlw b'00011111' ; first part of letter movwf PORTB call Delay ; Short delay (count down from 0xFF) ;Column 2 movlw b'10111' movwf PORTA ; rotate PORTA to next column 10111 (for some reason rotate wasn't working, so reverted back to movlw, any advice?) movlw b'00100100' ; movwf PORTB call Delay ;Column 3 movlw b'11011' ; rotate PORTA to next column 11011 movwf PORTA movlw b'01000100' ; movwf PORTB call Delay ;Column 4 movlw b'11101' movwf PORTA ; rotate PORTA to next column 11101 movlw b'00100100' ; movwf PORTB call Delay ;Column 5 movlw b'11110' movwf PORTA ; rotate PORTA to next column 11110 movlw b'00011111' ; movwf PORTB call Delay ;turn off last column movlw 0h movwf PORTB ;Cycle through the letter decfsz CYCLE,1 goto AAA1 return On 10/17/05, Phil Seakins <@spam@pseakinsKILLspamakamail.com> wrote: {Quote hidden}> > Scott, > > Can you show us one or two of your subroutines? It sounds like you > might have a lot of redundant code. I wonder why you don't have a > single subroutine, the character bit map info might be drawn from a table. > > A possible way to include only wanted routines is to disable ALL of > them with "remark" prefixes and then let them in one by one till you > don't get a compilation error. > > > >> scott larson wrote: > >> > >> >hi, > >> >i'm not very experienced with assembler directives, so i don't know if > >> this > >> >is achievable. > >> >i have an asm program that has many subroutines, each lights a > different > >> >letter on a 5x7 LED display. In my main program, i call whatever > >> subroutine > >> >I want, for example, to display "HELLO" : > >> > start > >> >call HHH ; light up H > >> >call Pause; > >> >call EEE; light up E > >> >call Pause; > >> >call LLL; light up L > >> >call Pause; > >> > call LLL; light up L > >> >call Pause; > >> >call OOO; light up O > >> >call Pause; > >> >goto start > >> > i have programmed the whole alphabet and other characters, but they > do > >> not > >> >all fit on the PIC. > >> >what i want to do is program only the ones that get called, and have > the > >> >assembler ignore the rest. > >> > i have been looking at #DEFINE, IFDEF, and IF statements, but i can't > >> seem > >> >to figure this out. > >> > can somebody point me in the right direction? > >> > i'm using MPLAB. >

scott larson wrote: > AAA > ;****Set up CYCLE counter > movlw CYCLES ;change this value to change the length of time the letter > is displayed, about 0x80 > movwf CYCLE ;register to move CYCLES into > AAA1 > ;Column 1 > movlw b'11101111' ;low column 1 (for common cathode display) > movwf PORTA > movlw b'00011111' ; first part of letter > movwf PORTB > ... This is now the second time you posted code that could not possibly have assembled with MPASM. If you want further help, you need to read and respond to my previous post. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com

the code does assemble in MPLAB. when i copy and paste, my browser takes out the space in the first column. when i view my previous post in a fixed-width font, there is a space in the first column. On 10/18/05, Olin Lathrop <KILLspamolin_piclistKILLspamembedinc.com> wrote: {Quote hidden}> > scott larson wrote: > > AAA > > ;****Set up CYCLE counter > > movlw CYCLES ;change this value to change the length of time the letter > > is displayed, about 0x80 > > movwf CYCLE ;register to move CYCLES into > > AAA1 > > ;Column 1 > > movlw b'11101111' ;low column 1 (for common cathode display) > > movwf PORTA > > movlw b'00011111' ; first part of letter > > movwf PORTB > > ... > > This is now the second time you posted code that could not possibly have > assembled with MPASM. If you want further help, you need to read and > respond to my previous post. > > > ***************************************************************** > Embed Inc, embedded system specialists in Littleton Massachusetts > (978) 742-9014, http://www.embedinc.com >

scott larson wrote: > the code does assemble in MPLAB. when i copy and paste, my browser > takes out the space in the first column. when i view my previous post > in a fixed-width font, there is a space in the first column. I'm viewing it in a fixed pitch font too, but I see no space. Neatness and clarity count. Make sure there are a few hard spaces before mnemonics before posting code here. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com

On Mon, 2005-10-17 at 18:35 -0400, Tom Sefranek wrote: > Close, it was the PIC18C452. > I have NEVER been even close to out of code space. Then you haven't done very much. > It takes a HLL Compiler to do that. What?? No, not at all. I've run out of code space multiple times, without an HLL. > Now RAM and cycles on the other hand... Well there you go. More often then not when approaching a problem a designer has choices as to what resources are more important. There are many cases where code space can be sacrificed to end up with more cycles and ram to play with. A good example of this is dealing with complex equations. While simply putting the equation into the PIC works, and doesn't use much code (since most of the math code would already be there for other purposes), it often ends up using a TON of cycles and quite a few ram locations. OTOH if you use a lookup table (with perhaps some small interpolation) you give up a lot of code space to free up a ton of cycles and ram. If you regularly run out of ram and cycles, and yet never run out of code space it SOUNDS like you aren't balancing things in such a way to make as much use of your hardware as possible. There's nothing wrong with this, it'll just mean you need a more powerful PIC to do the job then is technically required. In a hobbyist type environment this is fine, since an extra $2 for a more powerful PIC doesn't matter. In a professional environment this isn't that good, since your product will be more expensive then it needs to be. Sorry for being a little harsh, but saying an HLL is needed to run out of code space is simply incorrect. TTYL ----------------------------- Herbert's PIC Stuff: http://repatch.dyndns.org:8383/pic_stuff/

Herbert Graf wrote: > If you regularly run out of ram and cycles, and yet never run out of > code space it SOUNDS like you aren't balancing things in such a way to > make as much use of your hardware as possible. Or you needed that particular PIC because of its peripherals, pins, and/or processing power and the large code space just tagged along. > There's nothing wrong with this, it'll just mean you need a more > powerful PIC to do the job then is technically required. > > In a hobbyist type environment this is fine, since an extra $2 for a > more powerful PIC doesn't matter. In a professional environment this > isn't that good, since your product will be more expensive then it needs > to be. First, the distinction isn't between hobby and professional projects, but between low and high volumes. Hobby projects are just assumed to be low volume. Second, if you're making 5-10 units a year and each cost several 100K$, then the cost of the PIC is swamped by the cost of the development effort. In that case you want to chose the PIC that will require the least worrying about resources. An extra $2 times 20 PICs is worth it if you can save half an your by not having to worry about program memory usage. > Sorry for being a little harsh, Yes it is, especially when there is a legitimate reason to chose the biggest bestest and be done with it, and since Tom happens to be in that situation. > but saying an HLL is needed to run out > of code space is simply incorrect. No, but it helps. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com

Herbert Graf wrote: >On Mon, 2005-10-17 at 18:35 -0400, Tom Sefranek wrote: > > >>Close, it was the PIC18C452. >>I have NEVER been even close to out of code space. >> >> > >Then you haven't done very much. > > (Giggle) Nah! I guess I havn't done much... The NeuroFocus Brain Scanner with 28 18C452s, The MollyQ small animal machine with 48 18F4520s, The Fetal Oxy machine with 20 or so PICs, The Analysis Tower project with 5 or so PICs The Tech Marine controllers, (Olin's old project) and a BUNCH of odds and ends controllers supporting the research we do, Lots of Ham radio related stuff, Lots of solar projects, Heck, I even did some part of a project for Olin... Your right, I haven't done much. -- * | __O Thomas C. Sefranek spamBeGoneWA1RHPspamBeGoneARRL.net |_-\<,_ Amateur Radio Operator: WA1RHP (*)/ (*) Bicycle mobile on 145.41, 448.625 MHz hamradio.cmcorp.com/inventory/Inventory.html http://www.harvardrepeater.org