CCS/MSP430FR2311: Duty cycle for PWM above 350kHz

Part Number: MSP430FR2311

Tool/software: Code Composer Studio

i cant get perfect dutycycle for frequency above 350KHZ

when i changed from 10%-90% the duty cycle will only vary to 33% and 66%

Hello Nakkiran,

Can you give us more information on your timer configuration to generate the PWM?

I also attached the example project on how to set PWM with FR2311 device. This program generates two PWM outputs on P2.6/P2.2 using Timer_B configured for up mode. The value in CCR0, 512-1, defines the PWM period and the values in CCR1-2 the PWM duty cycles. Using ~1048kHz SMCLK as TBCLK, the timer period is ~488us.

timer_b_ex3_pwm.zip

Thanks,

Yiding 

From your symptom, I suspect you're running SMCLK=1MHz (i.e. you haven't changed it). At 333kHz this only gives you 3 clock ticks per PWM cycle, so you can only get 3 settings ("low resolution").

If you speed up SMCLK to 16MHz, you can get (16*3)=48 possible duty cycles. Example program msp430fr231x_CS_03.c (SLAC708B.zip, on the Tools and Software tab on the product page) has some code you can copy/paste to set SMCLK=16MHz.

cant find slac708b

how can i change that