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???
07/28/09 21:08
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#167983 - Dec
Responding to: ???'s previous message
Maarten Brock said:
Steve,

Steve M. Taylor said:
       XCH A,r0    ;Get r0
       DEC A
       JNZ nxtr1   ;Is it Zero ? Turn off the bit, else next bit
       clr P2.0 
nxtr1: XCH A,r0    ;PUT DECREMENTED register back !

 


Have you forgotten about DJNZ Rn? Or am I missing something?

Maarten


I was doing a DEC A and XCH it back. Yours is faster.

Mines not not quite right is it ? I need a catch when the port is clear to not do anything, so noting that...
 ;mine might be
       JNB P2.0,nxtr1    ; 2 cycles
       XCH A,r0          ; 1 cycle
       DEC A             ; 1 cycle
       JNZ nxtr1         ; 2 cycles
       clr P2.0          ; 1 cycle
nxtr1: XCH A,r0          ; 1 cycle (total 8 cycles/channel)          

 



 ;yours might be
       JNB P2.0,nxtr1  ;2 cycles
       DJNZ r0, nxtr1  ;2 cycles
       CLR P2.0        ;1 cycle
nxtr1: JNB P2.1,nxtr2
       DJNZ r1, nxtr2
       CLR P2.0
nxtr2: JNB P2.1,nxtr3

 


Frankly, I'm so out of practice, I'd forgotten DJNZ ! Doooh.

Steve


List of 29 messages in thread
TopicAuthorDate
Simple PWM to drive led            01/01/70 00:00      
   Loop lasts too long!            01/01/70 00:00      
      I put the delay...            01/01/70 00:00      
         Did you see?            01/01/70 00:00      
            didnt noticed!            01/01/70 00:00      
               Ok, try the following...            01/01/70 00:00      
                  the JMP            01/01/70 00:00      
                     I thought this was your intention...            01/01/70 00:00      
   Another try            01/01/70 00:00      
   is possible to filter the pwm output...            01/01/70 00:00      
      PWM from a Timer interrupt?            01/01/70 00:00      
      questions            01/01/70 00:00      
   best code until now            01/01/70 00:00      
      read replies            01/01/70 00:00      
         will lower refresh rate            01/01/70 00:00      
            Time to switch...            01/01/70 00:00      
            Wrong.            01/01/70 00:00      
               my code is doing what I want            01/01/70 00:00      
                  TIming            01/01/70 00:00      
                     FOR NOW!!!!            01/01/70 00:00      
                        The old story...            01/01/70 00:00      
               DJNZ            01/01/70 00:00      
                  Dec            01/01/70 00:00      
                     Do nothing?            01/01/70 00:00      
                        Speed            01/01/70 00:00      
                           slowdown            01/01/70 00:00      
                              Chico            01/01/70 00:00      
                                 Not yet...            01/01/70 00:00      
                                    good catch            01/01/70 00:00      

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