topic Internal cache for S12X in S12 / MagniV Microcontrollers

Internal cache for S12X

JadhavAj — Wed, 19 Dec 2007 16:43:46 GMT

Hi,

I intend to clear internal cache (instruction queue, data queue) for S12X. Please suggest if this is possible and how.

Thanks.

Regards,

Ajay

Re: Internal cache for S12X

kef — Wed, 19 Dec 2007 17:13:17 GMT

There's no data queue / cache in S12X.

There's only a instruction queue. Just branch/jump somewhere and queue will be "emptied and reloaded". Why do you want to clear instruction queue, are you doing something very smart?

Re: Internal cache for S12X

JadhavAj — Wed, 19 Dec 2007 20:20:07 GMT

I am writing RAMTest algorithm. One of the requirement is to clear the internal cache after writing to RAM and before reading back from RAM.

Do you mean if I make some branch/jump instruction, internal cache(instruction queue) will get cleared. Will this have some side-effect on existing code?

Re: Internal cache for S12X

kef — Wed, 19 Dec 2007 22:58:52 GMT

There's no cache in S12X. You shouldn't do anything to meet your requirement. Writing or reading internal/external RAM isn't cached or queued.

I believe you shouldn't care about instruction queue. You could need to clear it only hm... if your code runs in paged RAM, you write to RAM paging register and depending on instruction queue size you expect one or more instructions "skipped" on RAM page you are trying to map to...