Question about Leopard MPC5643L

[pabloprieto]

Hi guys,

I have a problem when I program my MPC5643L and is that all the DIOS get high level. I have two PWM that control two valves and when I program the MCU, the PWMs are activated. Any one knows if exist any configuration option to avoid this issue. I am working now in changing hardwardly the polarity of the signal, but this will be my last chance.

Any idea. Thanks in advance

Best regards

Pablo

[PetrS]

Hi,

During and after reset almost all GPIO pins are in high-z state, until you configure the PCR registers, for example weak pull-down/up etc.

The PWM module control the output once the PA field in PCR register is set for PWM function and when PWM.OUTEN register  is configured. In that case the polarity of the PWM output is done by PWM.SUBx.OCTRL[POLx] bits.

Regards,

Petr

[pabloprieto]

Hi Petr,

Are you sure that During and after reset almost all GPIO pins are in high-z state, because I'm trying with a pull down and it is not working, I always obtain high level.

Regards

Pablo

[PetrS]

Hi Pablo,

The state of the pin can be checked against a Pin summary table of the device Reference manual (chapter 3.4; http://cache.freescale.com/files/32bit/doc/ref_manual/MPC5643LRM.pdf) and/or SIUL PCR register description (chapter 47.5.2.8).

Maybe the external circuitry connected to the pin pulls it high and weak internal pull-down is not enough to hold it down.

Regards,

Petr

[pabloprieto]

Hi Petrs,

We have solved the problem. We were using very weak pull down. Now with an stronger one, it works perfectly, thank you very much for your support.

Best regards

Pablo

[pabloprieto]

Thanks Petr,

I will try with a pull down.

Regards,

Pablo