MSP430F5333 JTAG Question

Hi Nicholas,

On MSP430s that have shared JTAG pins with GPIOs, they always have the TEST pin. As you've mentioned, the tool will use this TEST pin to keep the GPIOs in JTAG mode. Then when you run the part without the debugger tool connected, as long as you have left the TEST pin disconnected (since it is internally pulled down), or have it externally pulled down, it will automatically default to GPIOs rather than JTAG functions.

You can find more details in the device user's guide as well as in this document, the MSP430 Programming via the JTAG interface User's Guide www.ti.com/lit/pdf/slau320 section 1.2.1.2 and 1.3.1.1. Just know however that the MSP-FET430UIF or MSP-FET tool is going to do this for you - the document will provide you more details on what's happening under the hood. The FET tool also uses the TEST and RST pin on devices that support SBW mode, to perform an entry sequence to tell the part to come up in 4-wire JTAG, SBW, or BSL mode (or start up as normal application) - there's more details in section in Figure 1-11 of the same document.

I hope this answers your question.

-Katie