My first foray into PWM

[gadelhas]

(without considering oscillator speed and PWM range limitations)

Then there's something about PWM that I didn't understand. HIGH/LOW using PAUSE for 500uS is not the same as a 1000uS period with 50% duty cycle?

Attachment 7531
Ooop, uS, not Us.

Robert

Yes, from that point of view, it is the same thing! (without considering oscillator speed and PWM range limitations)

[HenrikOlsson]

Then there's something about PWM that I didn't understand. HIGH/LOW using PAUSE for 500uS is not the same as a 1000uS period with 50% duty cycle?

Yes of course, 500us ON and 500us OFF is 50% dutycyle. But the period is 500us+500us = 1000us = 1ms = 0.001s - NOT 1s which you later wrote.

In your first post you indicated you wanted a PWM period of 1000us (a frequency of 1000Hz). In your second post you said you wanted a period of 1s (a frequency of 1Hz). It doesn't add up - that's all I was trying to say.

/Henrik.

[Demon]

Ooops, my bad. Didn't explain myself properly.

[richard]

how to flash a pulse led @ 1 hz on a pic18 @64mhz with no code overhead and no interrupts

for demon

'*  Name    : UNTITLED.BAS                                      *
'*  Author  : [select VIEW...EDITOR OPTIONS]                    *
'*  Notice  : Copyright (c) 2014 [select VIEW...EDITOR OPTIONS] *
'*          : All Rights Reserved                               *
'*  Date    : 29/11/2014                                        *
'*  Version : 1.0                                               *
'*  Notes   :   pic18f45k20                                                *
'*          :                                                 *
'****************************************************************
#CONFIG
  CONFIG  FOSC = INTIO67
  CONFIG  FCMEN = OFF
  CONFIG  IESO = OFF
  CONFIG  PWRT = OFF
  CONFIG  BOREN = SBORDIS
  CONFIG  BORV = 18
  CONFIG  WDTEN = ON
  CONFIG  WDTPS = 512
  CONFIG  CCP2MX = PORTC
  CONFIG  PBADEN = OFF
  CONFIG  LPT1OSC = OFF
  CONFIG  HFOFST = ON
  CONFIG  MCLRE = ON
  CONFIG  STVREN = ON
  CONFIG  LVP = OFF
  CONFIG  XINST = OFF
  CONFIG  DEBUG = OFF
  CONFIG  CP0 = OFF
  CONFIG  CP1 = OFF
  CONFIG  CP2 = OFF
  CONFIG  CP3 = OFF
  CONFIG  CPB = OFF
  CONFIG  CPD = OFF
  CONFIG  WRT0 = OFF
  CONFIG  WRT1 = OFF
  CONFIG  WRT2 = OFF
  CONFIG  WRT3 = OFF
  CONFIG  WRTC = OFF
  CONFIG  WRTB = OFF
  CONFIG  WRTD = OFF
  CONFIG  EBTR0 = OFF
  CONFIG  EBTR1 = OFF
  CONFIG  EBTR2 = OFF
  CONFIG  EBTR3 = OFF
  CONFIG  EBTRB = OFF
#ENDCONFIG

  define OSC 64
  
   osccon=$70   '4 mhz
    
     trisc=%11111001
  
   trisd.1=0   ' another led 
     T2CON = $4; // tmr2 prescale 0 and on
     PR2 = 255; // pwm period   ?
     CCP1CON = $c; // pwm mode
     CCPR1L = 127; // pw
     t1con=$43
     CCP2CON = 2
     t3con=3
     OSCTUNE.6=1 

   ; ccp1 out connects to t1ck in and pulse led connected to ccp2 out
   ; on     pic18f45k20  ccp1 out = portc.2
   ;                     ccp2 out = portc.1  
   ;                     ti ck in = portc.0

 

 
  
  
  
    
Main:
  latd.1= !latd.1       ;flash another led
  pause 500
  goto main

[Demon]

Neat, first I have to get my Charlie-plex going again. I broke it. LOL

Robert