The maximum clock frequency of the MSP430F6459TPZR is 25 MHz.
To configure the MSP430F6459TPZR for low power consumption, use the low-power modes (LPM3, LPM4) and adjust the clock frequency, disable unused peripherals, and use the built-in power management features.
Yes, the MSP430F6459TPZR can be used with an external crystal oscillator. The device has an internal oscillator, but an external crystal oscillator can be used for more accurate clocking.
The MSP430F6459TPZR can be programmed using the Texas Instruments Code Composer Studio (CCS) or IAR Embedded Workbench. The device can be programmed using the JTAG or Spy-Bi-Wire interfaces.
The MSP430F6459TPZR has 52KB of flash memory and 4KB of RAM.