Design Considerations for
3.1 Bootstrap Loader
The JTAG pins provide access to the Flash memory of the MSP430F device. On some devices, these pins must be “shared” with the device port pins, and this sharing of pins can complicate a design (or it may simply not be possible to do so). As an alternative to using the JTAG pins, MSP430F devices contain a program (a “Bootstrap Loader”) that permits the Flash memory to be erased and programmed simply, using a reduced set of signals. Application Notes SLAA089 and SLAA096 fully describe this interface. TI does not produce a BSL tool. However, customers can easily develop their own BSL tools using the information in the Application Notes, or BSL tools can be purchased from 3rd parties. Refer to the MSP430 web site for the Application Notes and a list of MSP430 3rd party tool developers.
Texas Instruments suggests that MSP430Fxxx customers design their circuits with the BSL in mind (i.e., we suggest providing access to these signals, e.g. via a header). Refer to section Device Signals below.
Refer to FAQ, Hardware #9) for a second alternative to sharing the JTAG and port pins.
3.2 External Power
The PC parallel port can source a limited amount of current. Owing to the ultra low power requirement of the MSP430, a
The
To connect
When an
When a Target Socket module is powered from an external supply, the external supply powers the device on the Target Socket module and any user circuitry connected to the Target Socket module, and the FET Interface module continues to be powered from the PC via the parallel port. If the externally supplied voltage differs from that of the FET Interface module, the Target Socket module must be modified so that the externally supplied voltage is routed to the FET Interface module (so that it may adjust its output voltage
