PWM ECE 4437-EMBEDDED SYSTEMS DR. GLOVER CHRISTOPHER AHN & KHOA VAN

WHAT IS COVERED AND WHAT IS NOT Cover: Count down mode and basic configuration to get the motor run. Not cover: Count up/down mode Dead band Interrupt Others

LOAD: Determines PWM period based on system clock ADown/BDown: determine pulsewidth COMPA/COMPB: we set the value to get Adown/BDown

ILLUSTRATION Example: System clock is 80[Mhz] (can be reduced). PWM Clock will be: 80[Mhz]/64=1.25[Mhz] (period is 0.8 [us]) We want: 2[ms] period. What is the Load value? Answer: LOAD= (2[ms]/0.8[us])-1

ILLUSTRATION Now we need to generate pulse width, We will generate 20% duty cycle for PWMA for this example HOW? Easy: LOAD is 100%, so 20%*LOAD is the value for COMPA.

SUMMARY OF THE CODE: Initialize and enable the Clocks Enable the PWM Modules Configure Pin types Set Duty Cycle Enable the gate Enable generators

CODING EXAMPLE

Can be found on page 489 in: spmu298a_TivaWare_Peripheral_Driver_Lib.pdf