An 80MHz oscillator

[Vizier87]

Hi guys,
I'm trying to ease my way in using a PIC32 in future. Since they work at 80MHz, I've combed around the site for the cheapest around Element14 and saw this one as the cheapest choice for the oscillator part. I wonder if there are other cheaper solutions?

Many thanks.

 

[Wp100]

Hi,

Seems most Pic32 have an internal oscillator as well as external sources.
Full details here, though you might need phd to understand it all !
One reason why the Pic16/18s remain so popular.
https://ww1.microchip.com/downloads/en/DeviceDoc/61112F.pdf

 

[Vizier87]

Hi wp100,
That clears a lot of problems there. Thanks a lot.
Are they better than the dsPIC30/33s actually? let's say I want to implement FEM while displaying some sort of real time graphical spectrum analysis using a color LCD panel?

 

[Gobbledok]

Hi Vizier,

I've had a month or 2 experience with the PIC32's now, they really are a totally different animal than the dsPIC's.

They have a bucket-load more RAM and they use a totally different core (MIPS). However because it's a PIC the peripherals are basically the same to use and the SFR's have familiar names. If you have any experience with other PIC's and C they are a breeze to learn but you will have to get acquainted with the data sheet. I'm not experienced by any means and picked it up quickly.

They are an excellent choice for color LCD's due to the PMP (Parallel Master Port) and the DMA (Direct Memory Access) allowing you to draw frames from a memory buffer and pictures etc. with virtually no CPU time used.

To answer your original question, you can use a wide variety of crystals for 80MHz, starting at 4MHz with the PLL enabled. You can also use the internal 8MHz RC oscillator with PLL for 80MHz.

 

[Vizier87]

Hi Gobbledok, thanks for your reply.
So you're saying it's better than dsPICs in that matter?

 

[Gobbledok]

Yeh they're a lot more suited to driving color LCD's than dsPIC's due to the reasons outlined above and also their faster speed helps too. Also, you can get FFT, advanced math, peripheral and many other libraries for the PIC32.

 

[Vizier87]

Yeh they're a lot more suited to driving color LCD's than dsPIC's due to the reasons outlined above and also their faster speed helps too. Also, you can get FFT, advanced math, peripheral and many other libraries for the PIC32.

Nice one. I certainly look forward to performing all those.

 

[Noggin]

I second what Gobbledok says. I've been using PIC32 for various commercial and consumer products, several of which use color LCDs, USB, and Ethernet. I use the internal oscillator with PLL to achieve the 80MHz clock rate on most projects. One customer decided they wanted the PIC32 to time stamp a lot of events, queue up the events, and send them to a server. Luckily, that was the one project that we actually used a 10 MHz crystal as the oscillator so we were able to get an acceptable accuracy from the RTCC module.

 

[Vizier87]

Thanks for the feedback there Noggin.

 

[phalanx]

There are a number of PIC24F devices that have dedicated graphics controllers in them now (as well as USB and ethernet). You would be running at 16MIPS on 16-bit data though. If you are working on a large volume item the cost savings could make it worth while. If you are only making a couple, your time is worth more than the cost difference between the 24F's and the 32's.

 

[Gobbledok]

There are a number of PIC24F devices that have dedicated graphics controllers in them now...

The inbuilt LCD controllers in PICs are for driving LCD segments/pixels directly. i.e. small (low pixel/segment count) LCD screens without a driver chip. They are not suitable for this type of LCD screen as far as I'm aware.