I am working with an ARM Cortex M3 chip (reference manual available here). I'm trying to get the baud rate of my USART communications right. Reading pages 613 onwards, I understand that the value I should set for
USARTDIV depends on the clock rate of AHB1 (since I am working with USART3, governed by the AHB1 clock).
Looking at pages 614 onwards, I see that the clock rate
f_PCLK can take many different values (8MHz, 12Mhz, etc.). However, I cannot see anywhere where I can set the speed of that clock.
How can I measure/change/read the speak of the AHB1 clock?