Post by thread:[PIC:] 16c54 scanner

Michael Johnston wrote: >Hi guys > I wrote a program that i adaptive with help from a friend to flash 12 leds tied to the 12 I/O Pins on c54. I have four routines that rotate the bit pattern through porta and portb forwards and backwards. My problem is that when the routine is going from porta to portb forward ra3 flashes so fast and jumps to portb bit0 so fast you can not see this happening. It also does this when going backwards from portb to porta. But it portb bit 7 that you dont see flashing. My friend told me the reason this was happening was because of the part i am using so i ported it to F84 and the program did the same thing in this port. I need so type of a delay but everything i try seems to mess my code up. >Thanks >Mike Johnston > >-- >http://www.piclist.com hint: To leave the PICList >.....piclist-unsubscribe-requestKILLspam@spam@mitvma.mit.edu > > Can you post the code so we can PIC through it :-) regards Tony -- http://www.piclist.com hint: To leave the PICList piclist-unsubscribe-requestKILLspammitvma.mit.edu

If all you need is a simple delay, here's what I use: Small delay, up to 769 cycles: movlw n ;}1 cycle movwf TEMP ;}1 cycle decfsz TEMP ;/\ goto $-1 ;__> 3n-1 cycles c=3n+1 where: c = cycles n = literal at first instruction, 1 =< n =< 256 (0x001 =< n =< 0x0100, where 0x000=0x0100) Nested delay, unlimited cycles: movlw n ;}1 cycle movwf TEMP ;}1 cycle loop (nested delay loop) ;/\ decfsz TEMP ; > nd+3n-1 cycles goto loop ;_/ c=nd+3n+1 where: c = cycles n = literal at first instruction, 1 =< n =< 256 (0x001 =< n =< 0x0100, where 0x000=0x0100) d = number of cycles in nested delay loop To calculate the length of delay, find the number of instruction cycles it will complete, and divide that by the number of instructions per second your PIC is running at (equal to the frequency of the internal oscillator divided by four). Chances are you will have to use a nested loop if what your are doing is a visual effect, where you can just plug in the first delay above into the second (max 197,633 cycles, about 2ms at 4MHz). If more cycles were needed, you could then take this delay, and nest it once again in another loop (max 50,594,817 cycles, about 51s at 4MHz, just make sure that the TEMP register is different in each loop. If all you are doing is blinking lights, delays this long will not matter, but in other applications this would be a considerable amount of dead potential processing time, and other methods of timing would be used. For more time critical applications, if there are no possible combinations of literals to get the exact number of cycles you need, you would simply find the combination with the closest number of cycles possible below the desired number, then add a few nop's. --Nick --- Michael Johnston <.....stoney40KILLspam.....EARTHLINK.NET> wrote: {Quote hidden}> Hi guys > I wrote a program that i adaptive with help from a > friend to flash 12 leds tied to the 12 I/O Pins on > c54. I have four routines that rotate the bit > pattern through porta and portb forwards and > backwards. My problem is that when the routine is > going from porta to portb forward ra3 flashes so > fast and jumps to portb bit0 so fast you can not see > this happening. It also does this when going > backwards from portb to porta. But it portb bit 7 > that you dont see flashing. My friend told me the > reason this was happening was because of the part i > am using so i ported it to F84 and the program did > the same thing in this port. I need so type of a > delay but everything i try seems to mess my code up. > Thanks > Mike Johnston > > -- > http://www.piclist.com hint: To leave the PICList > EraseMEpiclist-unsubscribe-requestspam_OUTTakeThisOuTmitvma.mit.edu __________________________________ Do you Yahoo!? Yahoo! Hotjobs: Enter the "Signing Bonus" Sweepstakes http://hotjobs.sweepstakes.yahoo.com/signingbonus -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

part 1 1012 bytes content-type:text/plain; charset=ISO-8859-1; format=flowed (decoded 7bit) Hi Michael, See new attached code. Assemble it in MPLAB and add the variabled PB_A and PB_B to the watch window in binary format. Comment out the delay_write subroutine calls like this... call delay_write to... ; call delay_write Now assemble and step through the code to see how it works. When happy, un comment the delay_write subroutine calls and program a chip to test. regards Tony Michael Johnston wrote: {Quote hidden}>Tony > Here is my code you asked for. My delay was adapted from some code on >the pic list archive. >thanks >Mike Johnston >----- Original Message ----- >From: "Tony Nixon" <Tony.Nixonspam_OUTENG.MONASH.EDU.AU> >To: <@spam@PICLISTKILLspamMITVMA.MIT.EDU> >Sent: Sunday, January 11, 2004 10:07 PM >Subject: Re: [PIC:] 16c54 scanner > > > -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads part 2 3282 bytes content-type:text/plain; name=54.asm (decoded 7bit) ;********************************************************************************************* LIST p=16c54c include "p16c5x.inc" radix hex ;********************************************************************************************* cblock 0x08 D1 D2 C1 PB_A PB_B endc ; same equ 0x01 ;********************************************************************************************** org 0x000 ;********************************************************************************************** start movlw 0x00 movwf PORTA ;porta all bits low tris PORTA ;porta all pins output movlw 0x00 movwf PORTB ;portb all bits low tris PORTB ;aportb all pins output movlw b'00000001' movwf PB_A ; used for PORTA LED on, RA0 = 0N to start clrf PB_B ; used for PORTB LED on, all OFF to start ;********************************************************************************************* ; Port A,b Forward ;******************************************************************************************** A_Left call delay_write ; write to port and delay to see it bcf STATUS,C ; shift LED bit left once rlf PB_A,same btfss PB_A,4 ; if PB_A bit 4 = 1, scan moves into PB_B goto A_Left ; not 1 clrf PB_A ; clear bits in PB_A movlw b'00000001' ; set LED ON in PORTB 0 movwf PB_B B_Left call delay_write ; write to port and delay to see it bcf STATUS,C ; shift LED bit left once rlf PB_B,same btfss STATUS,C ; PB_B = 0 and carry = 1 if all done goto B_Left movlw b'01000000' ; start portB moving right movwf PB_B B_Right call delay_write ; write to port and delay to see it bcf STATUS,C ; shift LED bit right once rrf PB_B,same btfss STATUS,C ; PB_B = 0 and carry = 1 if all done goto B_Right movlw b'00001000' ; set LED ON in PORTA 3 movwf PB_A ; PB_B = 0 A_Right call delay_write ; write to port and delay to see it bcf STATUS,C ; shift LED bit right once rrf PB_A,same btfss STATUS,C ; PB_A = 0 and carry = 1 is all done goto A_Right movlw b'00000001' ; start port A moving left again movwf PB_A goto A_Left ;********************************************************************************************** delay_write movf PB_A,W ; set port A and B LED movwf PORTA movf PB_B,W movwf PORTB movlw 0x7f ; delay movwf D1 clrf D2 delay_0 decfsz D1,f goto $-1 decfsz D2,f goto delay_0 retlw 0x00 ;********************************************************************************************** end -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

Tony thank you I will run this and see what happens Thanks again Michael Johnston ----- Original Message ----- From: "Tony Nixon" <KILLspamTony.NixonKILLspamENG.MONASH.EDU.AU> To: <RemoveMEPICLISTTakeThisOuTMITVMA.MIT.EDU> Sent: Monday, January 12, 2004 6:28 PM Subject: Re: [PIC:] 16c54 scanner {Quote hidden}> Hi Michael, > > See new attached code. > > Assemble it in MPLAB and add the variabled PB_A and PB_B to the watch > window in binary format. > > Comment out the delay_write subroutine calls like this... > > call delay_write > > to... > > ; call delay_write > > Now assemble and step through the code to see how it works. > > When happy, un comment the delay_write subroutine calls and program a > chip to test. > > regards > > Tony > > Michael Johnston wrote: > > >Tony > > Here is my code you asked for. My delay was adapted from some code on > >the pic list archive. > >thanks > >Mike Johnston > >----- Original Message ----- > >From: "Tony Nixon" <spamBeGoneTony.NixonspamBeGoneENG.MONASH.EDU.AU> > >To: <TakeThisOuTPICLISTEraseMEspam_OUTMITVMA.MIT.EDU> > >Sent: Sunday, January 11, 2004 10:07 PM > >Subject: Re: [PIC:] 16c54 scanner > > > > > > > > > -- > http://www.piclist.com hint: PICList Posts must start with ONE topic: > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > > ---------------------------------------------------------------------------- ---- > ;*************************************************************************** ****************** > LIST p=16c54c > include "p16c5x.inc" > radix hex > ;*************************************************************************** ****************** > cblock 0x08 > D1 > D2 > C1 > PB_A > PB_B > endc > ; > same equ 0x01 > ;*************************************************************************** ******************* > org 0x000 > ;*************************************************************************** ******************* {Quote hidden}> start > movlw 0x00 > movwf PORTA ;porta all bits low > tris PORTA ;porta all pins output > movlw 0x00 > movwf PORTB ;portb all bits low > tris PORTB ;aportb all pins output > > movlw b'00000001' > movwf PB_A ; used for PORTA LED on, RA0 = 0N to start > clrf PB_B ; used for PORTB LED on, all OFF to start > > ;*************************************************************************** ****************** > ; Port A,b Forward > ;*************************************************************************** ***************** {Quote hidden}> A_Left > call delay_write ; write to port and delay to see it > > bcf STATUS,C ; shift LED bit left once > rlf PB_A,same > btfss PB_A,4 ; if PB_A bit 4 = 1, scan moves into PB_B > goto A_Left ; not 1 > > clrf PB_A ; clear bits in PB_A > movlw b'00000001' ; set LED ON in PORTB 0 > movwf PB_B > > B_Left > call delay_write ; write to port and delay to see it > bcf STATUS,C ; shift LED bit left once > rlf PB_B,same > btfss STATUS,C ; PB_B = 0 and carry = 1 if all done > goto B_Left > > movlw b'01000000' ; start portB moving right > movwf PB_B > > B_Right > call delay_write ; write to port and delay to see it > bcf STATUS,C ; shift LED bit right once > rrf PB_B,same > btfss STATUS,C ; PB_B = 0 and carry = 1 if all done > goto B_Right > > movlw b'00001000' ; set LED ON in PORTA 3 > movwf PB_A ; PB_B = 0 > > A_Right > call delay_write ; write to port and delay to see it > bcf STATUS,C ; shift LED bit right once > rrf PB_A,same > btfss STATUS,C ; PB_A = 0 and carry = 1 is all done > goto A_Right > > movlw b'00000001' ; start port A moving left again > movwf PB_A > goto A_Left > > ;*************************************************************************** ******************* {Quote hidden}> delay_write > movf PB_A,W ; set port A and B LED > movwf PORTA > movf PB_B,W > movwf PORTB > > movlw 0x7f ; delay > movwf D1 > clrf D2 > delay_0 > decfsz D1,f > goto $-1 > decfsz D2,f > goto delay_0 > retlw 0x00 > > > > ;*************************************************************************** ******************* {Quote hidden}> end > > > > > > -- > http://www.piclist.com hint: PICList Posts must start with ONE topic: > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > > -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

On Tue, 2004-01-13 at 12:43, Michael Johnston wrote: > Tony > Here is my code you asked for. My delay was adapted from some code on > the pic list archive. > thanks You've a lot of unnecessary stuff and the delays are misplaced. I'm relatively new to PICs but these are my observations and example code, * don't need counter since last bit already serves as a limit so no need to check Z either. * before you set the next bit check it is not the last bit * set the next bit then delay not the other way around * don't need to clear C since your rotates should never carry and you never checked it anyway ;put your setup stuff here start_condition clrf PORTB ;clear all portb movf 0x01 movwf PORTA ;set only pin0 on porta pointaf btfsc PORTA,3 ;if bit 3 is lit goto change_ab ;then we're ready to change ports rlf PORTA,same ;otherwise rotate call delay goto pointaf change_ab clrf PORTA ;finished with porta for now bsf PORTB,0 ;set bit 0 on portb ;others are already off pointbf btfsc PORTB,7 ;if bit 7 is lit goto pointbr ;then we're ready to reverse rlf PORTB,same ;otherwise rotate call delay goto pointbf pointbr btfsc PORTB,0 ;if bit 0 is lit goto change_ba ;then we're ready to change ports rrf PORTB,same ;otherwise rotate call delay goto pointbr change_ba clrf PORTB ;finished with portb for now bsf PORTA,3 ;set bit 3 on porta ;others are already off pointar btfsc PORTA,0 ;if bit 0 is lit goto pointaf ;then we're ready to start again rrf PORTA,same ;otherwise rotate call delay goto pointar goto start_condition ;should never get to here ;but just in case -- 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

Michael, Let me try to explain what is going wrong by rewriting the comments in your code. I have not changed or removed any commands, just the comments. pascnt1 movlw 0x05 movwf C1 ;counter contains value 5 setbitaf clrf PORTB ;portb leds all off bsf PORTA,0 ;first led of porta is lit pointaf decf C1,f ;decrease counter by one call delay ;wait a bit bcf STATUS,C rlf PORTA,same ;change to the next led in porta btfsc PORTA,3 ;if the fourth led is lit goto pascnt2 ;time to switch ports ;but hang on we only just lit the ;fourth led. Don't we need to wait ;a bit? movf C1,f ;when PORTA,3 is lit, C1=2 so Z will ;never be set by this command btfss STATUS,Z ;Z is never set so we always execute ;the next instruction goto pointaf ;keep processing porta pascnt2 movlw 0x09 ;switching to portb so movwf C1 ;load counter with 9 setbitbf clrf PORTA ;turn all porta off ;remember this is only 5 instructions ;since we turned it on!! bsf PORTB,0 ;turn on portb's first led ..........etc Do you see how your delays are misplaced? A simple fix would be to insert another "call delay" immediately after pascnt2. You'll need to modify your reverse routines in a similar way. Also, to tidy up your code, ask yourself these questions; What does the counter do? What does checking PORTA,3 do? If the answers to these are the same then you most likely only need one of them. When will the Z flag be set? Can this ever happen? I hope all this is helpful. PICs are great fun to work with. Out of interest, what are you using to program them? Rob -- 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