AnsweredAssumed Answered

STM32L496QEI oscillator frequency error

Question asked by Dustin McIntire on Aug 30, 2017
Latest reply on Aug 30, 2017 by Clive One

I'm debugging a new board which uses the STM32L496QEI6 and found that the HSI and MSI clocks are running about 8% too slow which is way outside the specification. (This error shows up both on both the UART pins and TIM2 clock).  The VDD rail is set to 1.8V and measured to be 1.84V on the DUT.  There don't appear to be any noise problems with the 1.8V supply near the VDD pins .  Also this same schematic design has worked correctly with STM32L471QEI6 parts.  I've tested that these boards will run all the way up to 80MHz correctly so I don't suspect there is some type of supply sag problem.  I just have the clock offset error.  Is there a specific pin to probe for low voltage or some other item to check?