公开(公告)号：US20040068383A1

公开(公告)日：2004-04-08

申请号：US10610343

申请日：2003-06-30

Applicant: STMICROELECTRONICS S.A. ,  STMICROELECTRONICS LTD

Inventor： Hitesh Shah ,  Laurent Perier

IPC: G06F019/00

CPC classification number: H03L1/00

Abstract: A chip includes CPU (12), memories (13,14) for programs and data, peripheral units (18,19) for interacting with the outside world, and an internal RC oscillator (17) for providing clock signals. One of the peripheral units (18) includes a timer counter incremented at a frequency derived from the RC oscillator. The method does not try to change the frequency of the RC oscillator. Instead, an external calibration source (21) is connected to a capture input of the timer unit to provide a signal having a reference frequency, e.g. the mains frequency. The counter is sampled on active edges of that signal, and the sampled values are processed to derive a calibration ratio. After these calibration steps, a software correction is applied to parameters handled by programs stored in memory based on the calibration ratio to compensate for frequency variations of the RC oscillator.

Abstract translation: 芯片包括CPU（12），用于程序和数据的存储器（13,14），用于与外界相互作用的外围单元（18,19）和用于提供时钟信号的内部RC振荡器（17）。 外围单元（18）中的一个包括以从RC振荡器得到的频率递增的定时器计数器。 该方法不会改变RC振荡器的频率。 相反，外部校准源（21）连接到定时器单元的捕获输入，以提供具有参考频率的信号，例如， 电源频率。 在该信号的有效边沿对计数器进行采样，并处理采样值以导出校准比。 在这些校准步骤之后，基于校准比率对存储在存储器中的程序处理的参数应用软件校正以补偿RC振荡器的频率变化。