Can TIM3 PWM outputs be set to Open Drain?

[gbulmer]

Posted on September 12, 2010 at 15:13

Can TIM3 PWM outputs be set to Open Drain?

[Tesla DeLorean]

Posted on May 17, 2011 at 14:06

Wouldn't you just program the GPIO pins into the Alternate Function, Open Drain mode? instead of the normal Push-Pull (GPIO_Mode_AF_PP)

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_OD;

  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

  GPIO_Init(GPIOC, &GPIO_InitStructure);

Presumably you've checked the pins are in the 5V tolerant group?

[Tesla DeLorean]

Posted on May 17, 2011 at 14:06

Have you ever tried configuring the combination of PWM & Open Drain?

No, and motors aren't my deal. But I have modulated a tri-colour LED from TIM3/PWM on PC.06/07/08, and I have used OD on other pins. So I'm pretty sure the pin-drivers work as described, and they are the same whether they are driven by a GPIO or a peripheral (AF).

You might want to verify the function of these pins, and perhaps others,  in regular GPIO_Mode_Out_OD, in the absence of other circuitry, and confirm they behave in the manner you expect.

[gbulmer]

Posted on May 17, 2011 at 14:06

clive1 - Thanks for the confirmations, that helps a lot.

I'll test the pins as you suggest. I'll do that when I'm near an oscilloscope (hopefully tomorrow).

[gbulmer]

Posted on May 17, 2011 at 14:06

clive1 - thank you for responding. 

I apologise for my tardiness, I've been stressfully busy this week.

Yes the pins are in the 5V tolerant group.

Have you ever tried configuring the combination of PWM & Open Drain?

[gbulmer]

Posted on May 17, 2011 at 14:06

clive1 - sorry I forgot to pop back and acknowledge that you were correct.

It works!

Thanks for your help.