Peter Drescher
Lib to switch the clock speed of the ST Nucleo to 84MHz. The internal RC oscillator is multiplied with the PLL.
Dependents: Nucleo_spi_master_20MHz Nucleo_vs_Arduino_Speed_Test DMA_I2S_Test MPU9150AHRS ... more
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The ST Nucleo board is running on 16 MHz out of the box. To speed up the cpu to the maximum speed we have to change the clock setting. A call of SystemClock_Config_84MHz_internal(); will config the pll to generate 84MHz. This frequency is generated out of the internal RC oscillator. The frequency is not so stable like a crystal ! My board is fluctuate +- 40KHz at 84MHz at room temperature.
If you need a more precise timing source, you have to add a external crystal. You need : X3 8MHz crystal , C33 and C34 18pF 0603 , R35 and R37 0R 0603 or you can simply use wire to short this two resistor pads. A call of SystemClock_Config_84MHz_external(); will config the pll to generate 84MHz out of the 8MHz crystal oscillator.
If you want to use a different crystal or frequency : the STM32CubeMX tool is your friend :-)