Young, Simply pulling TEST high is not enough to jump to JTAG/SBW/BSL mode. Pulling TEST high makes the shared JTAG pins (in this part PJ.0-3) take the JTAG/SBW function, but it won't stop the part from executing code. To actually enter JTAG/SBW/BSL mode, you have to do a sequence on TEST + RST - see www.ti.com/.../slau320 Figure 1-12 JTAG Access Entry Sequences. This will show the behavior with different sequences on TEST and RST. The issue I mention is that sometimes noise on TEST can cause you to erroneously perform one of these sequences by causing edges on the TEST pin. E.g. see the SBW entry sequence - that only takes a series of a couple of edges on TEST and you can enter SBW mode even while RST stays high. I am unsure if the state of pins will change when you enter SBW/JTAG mode in this way - in normal JTAG/SBW entry you usually perform a device reset, but there are ways to connect to a running target without a device reset so I can't really guarantee what state your pins would be in if you erroneously enter JTAG/SBW mode. However your code would not run so your application would appear unresponsive. Regards, Katie
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