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Re: MCF547X bus error

by nop head :: Rate this Message:

I take it all back!

The XL Bus timeouts catch any gaps in the memory map. They terminate the cycle and can give an interrupt. It was just the default timeout value is about 16 seconds so I thought it wasn't working.

It seems the CPU will only hang if you have a flex bus chip select configured for external termination and nothing provides TA.

2009/3/11 nop head <nop.head@...>

Well yes I could have a power of two separate regions but not in a way that could fill all the gaps in my memory map.

I could also remove gaps by letting memories mirror, but then errant memory accesses would just go undetected. A big step backwards from where we were 20 years ago.

2009/3/11 Allon Stern <Allon.Stern@...>

On Mar 11, 2009, at 8:52 AM, nop head wrote:

Dave,
Sorry, my last reply was rubbish. The spare chip select will of course terminate the cycle, but only for one duff region.

Chris

Is this true? On the 5282 you define a chip select's base address and mask. You can define a large region and a discontiguous mask to define multiple regions for one chip select.

-
allon
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