This version of the oscillator system offers multiple oscillator frequencies. Four different RC oscillators with nominal frequencies 1, 2, 4, and 8MHz are present in the device. This version features automatic loading of the 1MHz calibration byte from the Signature Row. Because four different RC oscillators are present, four different calibration bytes are stored in the Signature Row. If frequencies other than the default 1MHz are desired, the OSCCAL register should be loaded with the corresponding calibration byte at run-time.