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Clocks & the Clock Tree
The MCU's heartbeat: internal RC vs external crystal vs PLL, and the clock tree that feeds the core and every peripheral, plus the flash-wait-state trap that hangs chips.
22 min read
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What's the difference between an internal RC oscillator and an external crystal, and when do you use each?What does the PLL do in the clock tree?Why must you set flash wait states before increasing the core clock?A peripheral's timing (UART baud, timer period) is wrong. How does the clock tree factor in?What's the correct sequence to switch the system clock to a PLL running off an external crystal?
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