about emi wait state setting

ss · ‎2008-03-07

Posted on March 07, 2008 at 13:58

ss · ‎2008-03-06

Posted on March 07, 2008 at 03:08

Hi

I use STR710.

When I use 48Mhz(Main Clock) with EMI_WAITSTATE(10), muc works very well.

But I changed Main clock to 32Mhz, also EMI_WAITSTATE(10), but MCU could not boot even if we change form CS0 to CS3.

How can I find EMI_WAITSTATE value ?

Is there any formula ?

Thank you

avelez · ‎2008-03-06

Posted on March 07, 2008 at 03:53

It depends on MCLK. If you low the clock on a 25%, I suppose you should increment the wait state in a 25%, so I'll consider a value of 13.

However, you'll get the best value though a trial-error procedure :-]

kleshov · ‎2008-03-07

Posted on March 07, 2008 at 13:58

Quote:

you'll get the best value though a trial-error procedure :-]

Even better, consult the timing sections of the datasheets involved. And use an oscilloscope to verify that the required access cycle timings are satisfied.