The same for TMR2REG and TRISBP, actualy...
And this line :

T2OVRFLW  btfss PIR1,1

would be more readable as :

T2OVRFLW  btfss PIR1, TMR2IF


And in this line :

          clrf PIR1,1  ;###STEP 8: Configure & Start PWM

note that the ",1" is the "access bank bit", not TMR2IF.
A "1" says you are using the bank according to the BSR, but
on the 18F1220, there is only one bank so, well...

*But*, I actualy *do* think you are trying to clear the TMR2IF flag here.
Then it should be :

          bcf  PIR1,1         ;###STEP 8: Configure & Start PWM

or better :

          bcf  PIR1, TMR2IF   ;###STEP 8: Configure & Start PWM

Always using symbolic constants instead of ",1" is one way
to protect yourself from *some* simple errors...

Jan-Erik.

-----Original Message-----
From: Jan-Erik Soderholm XA (TN/PAC)
Sent: den 25 september 2003 01:25
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: [PIC:] Using Full Bridge PWM Mode on 18F1220


What is CCPREG ?
Some constant of your own ?
What is it's value ?
Jan-Erik.

-----Original Message-----
From: gtyler [mailto:gtyler@DRUMMOND.ORG.ZA]
Sent: den 24 september 2003 23:53
To: PICLIST@MITVMA.MIT.EDU
Subject: [PIC:] Using Full Bridge PWM Mode on 18F1220


Hi I'm having problems getting the PWM to work in Full Bridge mode
I want to use all four pins that this mode produces, but when simulating
it in MPLAB SIM the PWM works in its normal mode (ie. only RB3 has PWM
pulses
on it instead of RB2 or RB3 and RB6 or RB7 being high during this time)

I followed the instructions in the data sheets.

If it will help here is a simplified version of my program(with irrelevant
bits removed)

I have labelled it according to the steps that are used in the 18C1220 data
sheet

          movlw b'11111111' ;###STEP 1:Configure PWM Pins as inputs
          movwf TRISB
          movlw d'255'  ;###STEP 2: Set PWM Period
          movwf PR2
          movlw CCPREG  ;###STEP 3: Set ECCP Mode to Full Bridge
          movwf CCP1CON
          movlw d'2'
          movwf CCPR1L  ;###STEP 4: Set PWM Duty Cycle

Note: Steps 5-7 are to do with automatic shutdown and other things like that
so I
      figure it is okay to leave it out.

          clrf PIR1,1  ;###STEP 8: Configure & Start PWM
          movlw TMR2REG
          movwf T2CON
T2OVRFLW  btfss PIR1,1
          goto T2OVRFLW ;###STEP 9: Wait for TMR2 Overflow and change PWM
ports to outputs
          movlw TRISPB
          movwf TRISB

I hope this is understandable :)
Thanks
Chris

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