The maximum clock frequency of the MSP430F6636IPZ is 20 MHz.
To configure the MSP430F6636IPZ for low-power operation, use the Power Management Module (PMM) to select the desired power mode (e.g., LPM3 or LPM4) and adjust the clock frequency and voltage regulator settings accordingly.
Yes, the MSP430F6636IPZ can be used with an external crystal oscillator. The device has an internal oscillator that can be bypassed to use an external crystal oscillator. The external crystal oscillator can be connected to the XT1 and XT2 pins.
The MSP430F6636IPZ can be programmed using the Spy-Bi-Wire (SBW) interface or the Joint Test Action Group (JTAG) interface. You can use the Texas Instruments Code Composer Studio (CCS) or IAR Embedded Workbench to develop and debug your code.
The MSP430F6636IPZ has 128 KB of flash memory available for program storage.