Go Down

Topic: higher voltage on output pin 8 & 9 - due (Read 199 times) previous topic - next topic

emmanuelbabu

Im using the following code to generate 65khz pwm at pin 8 & 9, and im getting an output voltage higher that 3.3V at these pins.....is this normal? am i doing something wrong? The board is powered via programming port and connected to my laptop.....DSO outputs are attached...

Code: [Select]

void setup()  {
pinMode(9, OUTPUT);
pinMode(8, OUTPUT);
}
 

void loop()  {
PWMC_ConfigureClocks(65000 *256, 0, VARIANT_MCK);

DutyRatio_Boost=200;
analogWrite(9, DutyRatio_Boost);
DutyRatio_Buck=127;
analogWrite(8, DutyRatio_Buck);}


outofoptions

Are you connected to a circuit?  Where are your test leads attached?

emmanuelbabu

nope..i havent connected the outputs to any circuit, i just got the required pwm and freq. and connected the leads to an oscilloscope..?why?

Sulimarco

Can you post a screenshot of your scope?

Marco

emmanuelbabu

hi...the screen shots are already uploaded..

Sulimarco

Ooops.... sorry I missed them...

It seems to me that the peak to peak measure function is reading the undershoot and the overshoot of the signals, even if these are not visible in the second shot and that your signals are completly normal.


Please see the last post in this thread.


undershoot overshoot


Marco

emmanuelbabu

#6
Feb 02, 2016, 08:41 am Last Edit: Feb 02, 2016, 08:47 am by emmanuelbabu
hi..

ive generated the waveform with the code in this post, and the output is directly taken from the PWM pin 9  & 8 , i cant understand why im getting spikes in the initial portion of the waveform? is this ok?? i m going to use it to drive a buck boost converter..?

emmanuelbabu

read your post.................thank you!!

Go Up
 


Please enter a valid email to subscribe

Confirm your email address

We need to confirm your email address.
To complete the subscription, please click the link in the email we just sent you.

Thank you for subscribing!

Arduino
via Egeo 16
Torino, 10131
Italy