Disable PST/DDATA signals on MCF5274

[anej]

I am trying to disable the PST and DDATA BDM signals on an MCF5274. This is to reduce emissions.

The manual states that setting the PSTEN bit in CCR to '0' will disable these signals. The problem is that it does not work for me. This bit is always '0' no matter what I write to it and the signals are still active.

Is there something special I have to do in order to read and write this bit? (The CPU is in supervisor mode).

Regards,

Anders

[MrBean]

PDDPAR and DDRDD registers to output GPIO. Should do what you want.

(didnt check the 527x manual, i'm only used to 521xx-525xx)

[anej]

This is not possible on MCF5274/MCF5275. The pins in question are not configurable as GPIO. The only way to disable the pins is using the CCR register but I can not get it to work as expected.

[PaoloRenzo]

You can't disable the PST signals on this part using that register

If your concern is EMI, switch to JTAG mode as a workaround (JTAGEN)

Regards

[PaoloRenzo]

 register should be something like this

[anej]

Where can I find the manual or errata that shows this?

/Anders

[PaoloRenzo]

Will update errata manual.

Sorry for the inconveniences this might caused to you

Regards

[TomE]

PaoloRenzo wrote (4 years ago):

> Will update errata manual.

I can't see any updated manuals or errata for that chip.

I'm having similar problems with the MCF5235. I can't set the PSTEN pin in the CCR, so I'm suspecting it might have the same problems as the MCF5274.

Does anyone know?

Tom