I'd agree with Olin.  In the 16F87x series you have two registers, =
CCPR1l and CCPR1H that affect the duty cycle.  You will need to break =
your DUTY word up into two bytes, and assign them to the low and high =
byte separately. =20

If you need help in how to accomplish this, just ask.=20

--Lawrence Lile
  ----- Original Message -----=20
  From: Olin Lathrop=20
  To: PICLIST@MITVMA.MIT.EDU=20
  Sent: Monday, October 29, 2001 3:04 PM
  Subject: Re: [PIC]: Hardware PWM at low frequency?


  >         The way I understand it, I should get 0% - 100% for a CCPR1L =
from
  0 -
  > 333.  For these lower frequencies, if I slowly increase the DUTY =
cycle up
  > to about CCPR1L =3D75 it ramps up to 100%.  They it stays at 100% =
until
  > ~CCPR1L =3D260 at which it instantly drops to 0%.  From CCPR1L =
=3D260 to 333
  it
  > again ramps up to 100%.

  I haven't looked at any of your code, but this makes perfect sense.  =
CCPR1L
  is an 8 bit register, so it can only hold 0 to 255.  If you try to =
write 256
  into it, you will only write the low 8 bits in reality, which are 0.


  ********************************************************************
  Olin Lathrop, embedded systems consultant in Littleton Massachusetts
  (978) 742-9014, olin@embedinc.com, http://www.embedinc.com

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