The previous slide covered the low frequency options, this slide looks at the high frequency choices. As with LFXT1, the DCO, or digitally controlled oscillator, is also available on all MSP430 devices. It is a fully integrated high frequency oscillator used most typically for CPU and peripheral clocking. It can be tuned to output over a wide range of frequencies as low as 100 kHz and up to >20 MHz depending on device family. Other advantages of this high frequency clock is that it is quite low power and can turn on in less than 6 µs, with some devices capable of waking in less than 1 µs to a stable high frequency clock. Both of these capabilities of the DCO are key advantages over external crystals and clocks, making the DCO a fundamental component of the MSP430’s ultra-low power operation. The FLL feature is actually an extension of the DCO in some devices that offers automatic tuning of the DCO output frequency compared to a low frequency clock reference such as a 32.768 kHz crystal. The next term is MODOSC, a module or peripheral oscillator. It is in the TI 5xx and 6xx families and sources a 5 MHz clock for automatic usage by modules such as the flash controller and ADCs. It is completely user independent and turns on/off as requested by the peripherals that use it. Lastly, there are XT1 and XT2. These are the high frequency oscillator circuits that interface with a crystal or resonator. The supported frequency range varies by device family. When an accurate high frequency clock is needed in an application such as USB or RF, usage of XT1 or XT2 is critical. Also note that some of TI’s smaller pin-count devices do not support one or both of these high frequency oscillators.