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what is the maximum speed of SPI clock with different PLL in ADSP21489


I am using ADSP21489 with 400MHz pll clock speed at this time I am trying generate 20MHz SPI clock but output of SPI slave data is corrupting when low clock speed lessthan 15Mhz slave is giving correct data.

Again I configured PLL to 350MHz at this time SPI slave data is courrepting in less speed that means <5MHz.

But in ADSP21489 datasheet SPI clock speed is 25MHz.I  am using SPI slave is AD7266 it supports 25MHz clock speed.

I am confusing how to configure SPI clock in different clock rate.

will you please assist me how to set SPI clock with different speeds.

Below example code is initializing of SPI and PLL is 400MHz

void SPI_InitForADC(unsigned int SPI_Flag)
/* Disable SPI so that earlier SPI configuration will be erased then below configure SPI as required for New SPI-ADC Device */
*pSPIBAUD = 8;        //BNaud rate 12.5Mhz   /* Setup the baud rate 25MHz =400Mhz/(4*4)
*pSPIFLG = (SET_DSXEN_BITS | SPI_Flag);  /* Setup the SPI Flag register using the Flag specified in the call */
*pSPICTL = (AUTOSDS | SPIEN | SPIMS | WL32 | MSBF | TIMOD1 | SMLS | GM );// | CLKPL);// | GM); /*CPHASE | CLKPL | TIMOD2 |*/ /* Now setup the SPI Control register */