• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 30 subscribers
  • Views 294 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Three level PWM

Victor Azevedo
Intellectual 725 points


Greetings, i was wondering what kind of code or implementation i need to do to be able to implement three level PWM into the TM4C123GXL launchpad.

I've been looking the datasheet's and i found the countup/down mode but the comparator always use positive values, from 0 to LOAD, can someone tell me how to implement three level PWM into tiva.

I already checked the examples, i've seen the functions avaiable but still can't tell how to manipulate the information, i hope someone can guide me through.

  • 0
    Guru 117855 points

    Victor Azevedo said:
    code or implementation i need to do to be able to implement three level PWM

    Greetings returned - yet we believe that your, "Three level PWM" may not be as universal as you suspect.

    For past 5+ years we've employed ARM MCUs in the operation of high torque/high current BLDC motors.  And - in that role - we impose "gate drivers" between the MCU's PWM outputs (6 of them) and the gates of our power, N-FETs.  Now it is these gate drivers - which have both "High Side" & "Low Side" inputs - which may "tri-state" the power FETs.  This tri-stating of the FETs occurs when the MCU does not drive (either) the high - or low - gate drive inputs.  During this time interval - the power FETs for that motor phase are in, tri-state.

    As to the MCU's ability to generate, "3 levels" - unless you convert the GPIO from output to input - we don't see that capability. 

    When we configure the GPIO into PWM generator mode - those outputs sequence between "normal/customary" output logic levels - there is no 3rd level!  And - as described above - that "3rd level" is the result of the gate driver's action - not the MCU's.