SLAU278AH May 2009 – March 2021
The JTAG pins provide access to the memory of the MSP430 and CC430 devices. On some devices, these pins are shared with the device port pins, and this sharing of pins can complicate a design (or sharing may not be possible). As an alternative to using the JTAG pins, most MSP430Fxxx devices contain a program (a "bootloader", formerly knows as the "bootstrap loader") that permits the flash memory to be erased and programmed using a reduced set of signals. MSP430™ Flash Device Bootloader (BSL) User's Guide describes this interface. See the MSP430 website for the application reports and a list of MSP430 BSL tool developers.
TI suggests that MSP430Fxxx customers design their circuits with the BSL in mind (that is, TI suggests providing access to these signals by, for example, a header).
See FAQ 10 for a second alternative to sharing the JTAG and port pins.