ColdFire/68K Microcontrollers and ProcessorsのトピックRe: Disable PST/DDATA signals on MCF5274

Disable PST/DDATA signals on MCF5274

anej — Fri, 08 May 2009 22:36:58 GMT

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

Re: Disable PST/DDATA signals on MCF5274

MrBean — Tue, 12 May 2009 23:47:26 GMT

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

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

Re: Disable PST/DDATA signals on MCF5274

anej — Wed, 13 May 2009 20:41:00 GMT

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.

Re: Disable PST/DDATA signals on MCF5274

PaoloRenzo — Thu, 14 May 2009 01:43:28 GMT

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

Re: Disable PST/DDATA signals on MCF5274

PaoloRenzo — Thu, 14 May 2009 01:57:32 GMT

Re: Disable PST/DDATA signals on MCF5274

anej — Thu, 14 May 2009 13:46:44 GMT

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

/Anders

Re: Disable PST/DDATA signals on MCF5274

PaoloRenzo — Thu, 14 May 2009 21:30:18 GMT

Will update errata manual.

Sorry for the inconveniences this might caused to you

Regards

Re: Disable PST/DDATA signals on MCF5274

TomE — Mon, 15 Jul 2013 04:30:04 GMT

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