1.前言

OSC模块是一个晶体振荡器。 该模块使用晶体或谐振器与外部连接，为MCU产生一个参考时钟。

主要为下图红色框住的部分

2.特性和模式

Supports 32 kHz crystals (Low Range mode)
? Supports 3–8 MHz, 8–32 MHz crystals and resonators (High Range mode)
? Automatic Gain Control (AGC) to optimize power consumption in high frequency
ranges 3–8 MHz, 8–32 MHz using low-power mode
? High gain option in frequency ranges: 32 kHz, 3–8 MHz, and 8–32 MHz
? Voltage and frequency filtering to guarantee clock frequency and stability
? Optionally external input bypass clock from EXTAL signal directly
? One clock for MCU clock system
? Two clocks for on-chip peripherals that can work in Stop modes

3.框图

OCC模块使用晶振产生三个滤波后的晶振时钟信号：

1. OSCCLK:用于MCU

2.OSC32KCLK:

3.OSCERCLK:用于片上外设

OSCERCLK和OSC32KCLK可以工作在低功耗模式

4.OSC信号描述

5.外部晶振连接

6. 外部clock连接

7. Memory Map/Register Definitions

TODO

8.功能描述

8.1 OSC模块状态