Microcontroller

Discussion in 'General Electronics Chat' started by shankar M, Apr 28, 2014.

  1. shankar M

    Thread Starter New Member

    Mar 27, 2014
    16
    0
    What is difference between the operating speed and internal bus frequency IN Micro controller?
     
  2. ericgibbs

    AAC Fanatic!

    Jan 29, 2010
    2,503
    380
    hi,
    If 'operating speed' is the crystal frequency and the 'operating bus frequency' is the Instruction cycle time, then for most MCU's and PIC's it is a divide by 4 of the crystal frequency.

    This will give 4 internal clock cycles for the CPU logic for each program Instruction.

    E
     
  3. Papabravo

    Expert

    Feb 24, 2006
    10,149
    1,791
    The relationship is arbitrary. It depends on the internal architecture of the microcontroller. As has already been noted many PIC devices have a 4:1 ratio. Many 8051 parts have a 12:1 ratio, and many RISC machines have a 1:1 ratio. Sorry -- there is no general rule.
     
  4. BobTPH

    Active Member

    Jun 5, 2013
    784
    114
    Only 8-bit PICs have the 4:1 ratio. The 16-bit ones are 2:1 and the 32-bit are 1:1.

    Bob
     
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