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Tiva C Series TM4C123G LaunchPad Evaluation Board

Dragu Mircea
Prodigy 30 points

Hi,

When i use this development board, by default mcu has the 16 Mhz frequency (PIOSC).
What i want to do is to measure with a salae osciloscop if the frequency is 16 Mhz ?
But i dont have the pins pulled out on the J1, J2, J3, J4 headers.
How is possible to measure the frequency ?
Thank you in advance.

  • 0
    Guru 117855 points

    You should be able to configure an MCU's Timer (which "routes to" a "board header") - to operate in PWM Output Mode - set @ 50% duty cycle.     

    It is "usual" that you chose (some) integral division of the System Clock (PIOSC) in your case - as input to your Timer - and it is this,  "Frequency Divided REPLICA" - which will appear - at your desired header.

    You may note that (some) deviation from 16MHz IS to be expected - and will (likely) change w/temperature, aging &  (future)  MCU process.     Better frequency stability is achieved - as you know - via a properly installed crystal & related support components...

  • 0
    Guru 117855 points

    Dragu Mircea said:
    I dont have the pins pulled out on the J1, J2, J3, J4 headers.

    My friend - to earn "extra credit" - and to confirm your findings - by a, "VERY Quick Glance" @ MCU Manual - the following is noted:

    Timer           MCU Pin   Header

    T0CCP0      PB6           J2
    T1CCP0      PF2           J4
    T2CCP0      PB0          J1
    T0CCP1      PF1          J3

    You may note that I've found,  "FOUR Different Headers" - to best accommodate your needs.    

    It is "unclear"as to your meaning,   "Don't have the pins pulled out!"      They appear,  very much,  "Present and Ready/Waiting to satisfy your "frequency measuring" desire..."