Very Low Oscillator

The MSP430 has a very low power oscillator. The VLO frequency is ~9-12kHz and needs to be calibrated before use. Calibration uses the MSP430's Digitally Controlled Oscillator (DCO) which has been calibrated to +/- 1% during manufacturing to calibrate the VLO. This calibration can be done once on startup as long as the temperature remains fairly consistent; if your application will require operation at different temperatures then you may need to calibrate the VLO more often, or just use an external 32kHz xtal in lieu of the VLO.