Explanation of several clock frequencies in LPC2478

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Explanation of several clock frequencies in LPC2478 [Copy link]

The full-English datasheet includes several names such as CCLK and PCLK. Their specific meanings are as follows: There are three crystal oscillators in LPC2478. One is the Main Oscillator, one is the Internal RC Oscillator, and one is the RTC Oscillator. Internal RC Oscillator: Built-in crystal oscillator, 4MHz. It has two main uses: 1. The clock source of the watchdog; 2. As the clock source to drive the PLL. Main Oscillator: 1-24MHz, used as the clock frequency of the CPU, called CCLK. It can pass through the PLL phase-locked loop or not. After passing through the PLL, the clock frequency can be increased to greater than 24MHz; when the Main Oscillator is divided, it is used as the clock frequency of some peripherals, and the output frequency is called PCLK. RTC Oscillator: RTCLK, 32.768MHz. It is mainly used as the clock source of the real-time clock. Of course, it can also be used as a watchdog to drive the PLL and CPU clock frequency.