Can't Set PLLI2SCFGR

solomonviveros · ‎2014-03-18

Posted on March 18, 2014 at 18:39

I'm trying to configure the I2S pll for what will ultimately be 8KHz sampling and using the STM32F4xx_ClockCOnfiguration_V1.1.0, I get values of

PLLI2S_N = 256

PLLI2S_R = 5

for a crystal of 8MHz and HCLK at 168MHz...

Even when I go to system the system init c file, I step through the portion of code that sets the values before enabling the pll and R = 3, N = 258 initially; I can modify the R register when viewing the registers within keil, but I can't modify what would be N -- any suggestions on what I can try would be much appreciated.

Processor: STM32F405RGT6

solomonviveros · ‎2014-03-18

Posted on March 18, 2014 at 18:52

Found the issue -- I used the project[which had a different N/R configuration] as the foundation for a bootloader that runs before the application and it's there[didn't remove the I2S PLL init code from the system_stm32f4xx.c] that the I2S pll was enabled to 258 and 3...doh!