[PIC] PWM Output compare datasheet question

[Mark E. Skeels]

Hello, List.

After a long hiatus using MSP430 I am considering a PIC for a new design.

I want a PIC24 with 4 PWM outputs.

Using Microchip's parametric search, I have a list on my browser
indicating PIC24H parts with quote "4 -std. PWM" unquote; one of which
is the PIC24HJ64GP202.

However, it appears that there are only 2 output compare I/O pins, OC1
and OC2.

So, effectively, I can only get 2 PWM channels outside of this PIC.......

Am I missing something? Or is this correct? If so, what is the reason
for 4 PWM if only two can get outside the PIC?

Thanks,
Mark

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[Adam Field]

> So, effectively, I can only get 2 PWM channels outside of this PIC.......
>
> Am I missing something? Or is this correct? If so, what is the reason
> for 4 PWM if only two can get outside the PIC?

Going off the datasheet, you have four outputs. The peripherals are
mappable to different pins. See the output chart on page 130 detailing
OC1-4. And on page 165 you have the details of OCxCON 1-4, the output
control register. The PIC24H family reference has more information on
output compare modes.

[Mark E. Skeels]

Thanks, I got it confused with the PIC24HJ32GP202.......

Mark

[Olin Lathrop]

Mark E. Skeels wrote:
> Using Microchip's parametric search, I have a list on my browser
> indicating PIC24H parts with quote "4 -std. PWM" unquote; one of which
> is the PIC24HJ64GP202.
>
> However, it appears that there are only 2 output compare I/O pins, OC1
> and OC2.

I haven't looked up that part, but Microchip has two separate PWM
peripherals for the dsPIC line. The one that is more like the PWM module of
16 and 18 PICs is called "output compare", whereas the new fancy PWM module
is called PWM. So they may be counting PWM modules, not output compare
modules. Or perhaps they are lumping them together if this chip has 2 OC
and 2 PWM modules.

The parametric search has its uses, but there are sometimes errors.

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[Alan B. Pearce]

>I haven't looked up that part, but Microchip has two separate PWM
>peripherals for the dsPIC line. The one that is more like the PWM
>module of 16 and 18 PICs is called "output compare", whereas the
>new fancy PWM module is called PWM.

Maybe on the 18 series, or dsPic series, but on the 24 series they call it
"Output Compare with Dedicated Timer". Section 35 of the family reference
manual. Similar for the Input Capture.