13.11 Fast RC Oscillator

The on-chip 8 MHz Fast RC Oscillator (FRC) is intended to be a fast, with precise frequency, internal RC oscillator. The FRC supports calibration to ± 0.25% accuracy pre-package. However, package-induced stress lowers the accuracy.

The FRC oscillator is accurate to provide the clock frequency necessary to maintain baud rate tolerance for serial data transmissions. FRC is enabled with conditions in Enabling the FRC; otherwise, it is not enabled. Power-on Reset sets NOSC[3:0] = 0000; therefore, it is always ON when powered-up.

The oscillator module provides a 6-bit wide user tuning adjustment capability using the OSCTRM.TUN[5:0] bits.