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STM32F407 Discovery Board timers run faster than custom board

Posted by bg02478 on December 5, 2014

FreeRTOS on Discovery board one tick = 1 msec FreeRTOS on custom board one tick = 10 msec (same code as running on Discovery Board) Uart code Interrupt driven runs on both boards ADC/DMA Interrupt driven code runs on both boards

Where is the setup for external crystal vs. internal oscillator? Would this explain the factor of 10 slower ticks? If not, what do I change? Just some FreeRTOS parameters? Would this affect the operation of GPIO pins?

Thanks


STM32F407 Discovery Board timers run faster than custom board

Posted by rtel on December 5, 2014

You have to tell FreeRTOS the speed at which the clock is running using configCPUCLOCKHZ in FreeRTOSConfig.h. How you configure the clock is outside the scope of FreeRTOS, and FreeRTOS has no way of knowing this (unlike a BIOS based system such as a PC there is no location it can read this information from).

Regards.


STM32F407 Discovery Board timers run faster than custom board

Posted by bg02478 on December 5, 2014

Thanks, I think I need to fix SystemInit() in system_stm32f4xx.c


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