ColdFire/68K Microcontrollers and ProcessorsのトピックSTOP mode on MCF523x

STOP mode on MCF523x

anance — Wed, 02 May 2007 22:29:41 GMT

Hello Coldfire Group:

I am having trouble getting my 5232 part to go into low power stop mode.

I set the LPCR regsiter to 0xC8.

I set the LPICR register to 0xF0.

I issue the STOP instruction with a 0x2700 following.

I do enter the STOP instruction because execution halts. I am at the STOP

because when I am on the BDM and I halt, my PC is right after the STOP.

But the CLKOUT is still running and the current does not fall much.

The documentation says that CLKOUT should stop when the STPMD bit in LPCR is hi.

I have read back the registers and all seems OK.

The LPICR reads back as oxFF and resets to 0x0F. Not sure why that is since the manual

says that it defaults to 0x00.

It seems that I am entering STOP but it is not turning off clocks to the CORE, etc.

It is like the ENBSTOP bit is not set in the LPICR register.

Any ideas.

Thanks,

Allen

Re: STOP mode on MCF523x

macl — Wed, 23 May 2007 20:51:50 GMT

Try setting bit 4 of the LPCR register. I'm not very familiar with this particular device, however other similar devices offer 4 levels of stop modes which are controlled by bits 3 & 4 of that register. This may not be the case with this device, however its worth a shot.

Re: STOP mode on MCF523x

admin — Thu, 01 Nov 2007 23:30:50 GMT

I had the same problem with the MCF52210. Setting the DISCLK bit of the SYNCR register finally disabled the CLKOUT pin. That leaves me wondering what the STPMD bits really do. Nothing?

Message Edited by jtsmith on 2007-11-01 04:33 PM