Menu

Clarification of default clock speed

2016-09-27
2016-09-27
  • Sleepwalker3

    Sleepwalker3 - 2016-09-27

    In the #Chip section of the GCB help it says

    If speed is not present the compiler will select a frequency default frequency that should work.

    If the chip has an internal oscillator, the compiler will use that and pick the highest speed it supports.

    According to the data sheet for the 18F2525, the INT OSC can run up to 8MHz and by using the PLLEN the chip can run at 32Mhz. The help file comment above suggests this chip would run at 8MHz if no speed specified, but I wondered if it meant the highest speed the INTOSC supports (8MHz), or the highest speed the chip supports (32Mhz)?

     
    • Anobium

      Anobium - 2016-09-27

      If no oscillator chosen then the comoiler will set best option to use the Int Osc, if ChipMhz > 4 it will use HS and then if 4 > ChipMhz > ChipIntOsc use XT.

      Looking at the compiler code the PLL in not set, therefore, you need to set PLL. I this is incorrect I am sure Hugh will correct me. :-)

       

Log in to post a comment.