RT1176 SEMC SDRAM sdramconfig.tPrescalePeriod_Ns value

[Boscfab]

Hi everyone,
I'm trying to configure the parameters of the SEMC for my SDRAM bank with RT1176.
In the various parameters, in the EVB settings the value
"sdramconfig.tPrescalePeriod_Ns" it's "160 * (1000000000 / clockFrq)".

NOTE: EVB use 2x16bit SDRAM mod.W9825G6KH-5I with CLK=200MHz.

I use different SDRAM chips with 166MHz CLOCK but I don't know what data must be use to calculate this parameter; I have configured all the other parameters correctly but I don't understand this.
Does anyone know how to configure this parameter or can point me to an APPNOTE that describes it.

Thank you,

Fabio

[Omar_Anguiano · Accepted solution]

Hello
I hope you are well.

Prescaler period is used as a clock cycle count unit for refresh and bus idle timer period. Please refer to this example:

Best regards,
Omar

[Boscfab]

Perfect, the answer is exhaustive!
Is there a SEMC controller AppNote that describes how to optimize the setup of the various parameters?

The RT117xx family data sheet does not contain these useful explanations....

Many Thanks,

Fabio