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AN53313 - Real Time Clock Calibration in Cypress nvSRAM | サイプレス セミコンダクタ

AN53313 - Real Time Clock Calibration in Cypress nvSRAM

最終更新日: 
2020 年 5 月 28 日
バージョン: 
*E

AN53313 describes the Real Time Clock (RTC) calibration feature in Cypress nvSRAM that helps to maintain precise system time by compensating for the crystal frequency error.

はじめに

The Real Time Clock (RTC) in Cypress nvSRAM is driven by a crystal oscillator, with an external crystal having a nominal frequency of 32.768 kHz. Most 32.768-kHz crystals have a frequency tolerance of ±20 parts per million (ppm) at +25 °C. This frequency tolerance results in timing error over a long period of time. For example, a crystal with 20-ppm error in nominal frequency can drift the clock accuracy by 52 seconds in a month. You can compensate this drift by using  the calibration feature in the nvSRAM RTC.

 

Calibration Circuit Block Diagram

翻訳版のドキュメントは参照用です。設計開発に携わっている場合には、英語版のドキュメントを参照されることをお勧めします。