The BSL is not started by the BSL RESET vector if:
- There are fewer than two rising edges at the TEST pin while
RST/NMI is low.
- The TEST pin does not stay high after the TEST pin second rising edge when
RST/NMI rises from low to high.
- JTAG has control over the MSP430 MCU resources.
- The supply voltage, VCC, drops below its threshold, and a power-on reset (POR) is executed.
- The
RST/NMI pin is configured for NMI functionality (the NMI bit is set).
- If the TCK and TMS pins are left floating, the device can unintentionally enter JTAG mode. To avoid this issue, apply the recommended external termination. Add a 47-kΩ pullup resistor and a 1-nF pulldown capacitor on TCK and TMS. Stronger termination might be needed depending on noise in the system.