18F26K80 Serial setting sanity check and 4xPLL.


Closed Thread
Results 1 to 21 of 21

Hybrid View

  1. #1
    Join Date
    Aug 2011
    Posts
    453


    Did you find this post helpful? Yes | No

    Default Re: 18F26K80 Serial setting sanity check and 4xPLL.

    Great.

    Keep us posted on how it goes. I'd be interested to know if you have any problems with peripherals operating at those speeds, esp the builtin CAN controller.

  2. #2


    Did you find this post helpful? Yes | No

    Default Re: 18F26K80 Serial setting sanity check and 4xPLL.

    I also had a bad/fake 20mhz resonator.

    I then tried some Farnell ones and decent crystals all worked ok, even at 96mhz.

    The board actually worked in the car at 96mhz but that is overspec (12mhz) for the 10mhz MCP2515 CAN controllers SPI so I dialled the PIC back to 80mhz for reliability and (10mhz SPI)

    So a decent increase in speed over 64mhz at zero cost so far.

    Now back to the other thread to do some code speed optimisation before I add additional functionality with my extra free time.

  3. #3
    Join Date
    Oct 2005
    Location
    Sweden
    Posts
    3,604


    Did you find this post helpful? Yes | No

    Default Re: 18F26K80 Serial setting sanity check and 4xPLL.

    I'll admit, I've been sceptical about relying on overclocking for something that is actually being used but I suppose if it works at 96MHz(!) then dialing it back to 80MHz does provide some margin.
    Since it's going to end up in a car I'd probably test it at something other than room temperature before banking on the extra instruction cycles. I know you said it did work in the car at 96MHz but at what temperature?

    Looking forward to the optimisation thread!

  4. #4


    Did you find this post helpful? Yes | No

    Default Re: 18F26K80 Serial setting sanity check and 4xPLL.

    To be fair it worked ok at 64mhz without any optimisation I'm just being greedy and trying to free up/gain some cycles in advance of other stuff.
    I have a heat gun and freeze spray so it's pretty easy to stress it.

    It's been working fine in the summer sun for last two days at 80mhz.
    30-35C in the car.

Similar Threads

  1. Bytes roll over sanity check
    By retepsnikrep in forum mel PIC BASIC Pro
    Replies: 2
    Last Post: - 18th October 2020, 07:23
  2. Setting RTC by Serial input
    By jamie_s in forum Code Examples
    Replies: 1
    Last Post: - 26th November 2015, 13:57
  3. timer0 10ms setting check
    By longpole001 in forum mel PIC BASIC Pro
    Replies: 9
    Last Post: - 1st July 2015, 10:36
  4. looking for a quick sanity check
    By cncmachineguy in forum Serial
    Replies: 13
    Last Post: - 13th November 2010, 18:53
  5. Block Check on Serial Comms.
    By Mark Scotford in forum mel PIC BASIC Pro
    Replies: 4
    Last Post: - 15th June 2005, 09:27

Members who have read this thread : 3

You do not have permission to view the list of names.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts