ColdFire/68K Microcontrollers and ProcessorsのトピックSwitching mini-flexbus modes during runtime on M5225x, M52259

Switching mini-flexbus modes during runtime on M5225x, M52259

juanee — Wed, 02 Sep 2009 06:16:05 GMT

Hello everyone,

I am new to the M52259 Coldfire and I have read the AN3854 Mini-FlexBus.pdf (Rev. 0, 04/2009) application note concerning this topic.

My question... am I able to switch mini-flexbus modes (non-multiplexed to multiplexed and back again) at any time during runtime?

The reason: I wanted to control an asyncronous RAM (that has a 16 bit data bus) and a Flash NAND (that has an 8 bit data bus), but I wanted to have 16 bit data access to the RAM).

thanks,

juanee

Re: Switching mini-flexbus modes during runtime on M5225x, M52259

scifi — Wed, 02 Sep 2009 18:23:11 GMT

Hi Juanee,

Have a look at register definitions for CSCR0 and CSCR1. You will find that each chip select has independently configurable multiplexed mode and bus width.

Regards,

- mike

Re: Switching mini-flexbus modes during runtime on M5225x, M52259

juanee — Mon, 14 Sep 2009 10:10:41 GMT

Hello Mike,

I read what you suggested and I understand better now how it works. Thanks.

But, another question though...

Am I able to switch back and forth between the mini-flexbus mode and general purpose IO (PTE, PTF PTG, etc) during runtime?

Thanks,

juanee

Re: Switching mini-flexbus modes during runtime on M5225x, M52259

scifi — Mon, 14 Sep 2009 14:45:46 GMT

juanee wrote:

Am I able to switch back and forth between the mini-flexbus mode and general purpose IO (PTE, PTF PTG, etc) during runtime?

I think you should be able to do this. I haven't tried this myself, though...

Re: Switching mini-flexbus modes during runtime on M5225x, M52259

usingbothmuxand — Thu, 01 Apr 2010 21:12:10 GMT

I am facing same problem with this device.

my RAM is accessed as x8 bit and EoPDH device as x16 bit peripheral.

Is it possible to use FB_ALE/FB_CS1_BAR as FB_ALE in multiplex mode and as FB_CS1_BAR in non-multiplex while external devides are selecting by CS0 and CS1 signal?

See my block diagram...for that I have attached it.

FB_ALE/FB_CS1_BAR is routed to RAM and x16 latch by FB_CS0_BAR.

conditions is:::

if(FB_CS0_BAR==0)

FB_ALE <= FB_ALE/FB_CS1_BAR // to x16 latch

else

FB_CS1_BAR <= FB_ALE/FB_CS1_BAR // to RAM

Thanx...

Re: Switching mini-flexbus modes during runtime on M5225x, M52259

usingbothmuxand — Sat, 03 Apr 2010 11:27:49 GMT

Hi everybody,

Anybody plz reply me.

Is FB_ALE/FB_CS1_BAR may work as FB_ALE in mux mode and FB_CS1_BAR in non-mux mode for different chip selects at run time? Bcs i need minimum two chip selects in my system...

Is My design right?

Thanx...

Re: Switching mini-flexbus modes during runtime on M5225x, M52259

juanee — Tue, 14 Jun 2011 03:39:12 GMT

"Am I able to switch back and forth between the mini-flexbus mode and general purpose IO (PTE, PTF PTG, etc) during runtime?"

To answer my own question, the answer is YES. I have an external memory on the mini-flexbus that also needs the PTE, PTF ports as GPIO (to interface to another device).

Juan

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