TSTME/TSC —
The inactive state of this pin is five volts. Pulling it low enables special test mode, but the MCU cannot enter test mode unless the state of a bit in one of the test mode registers is changed by the software. Although this should happen only if the software is corrupted, to prevent entering special test mode, put a 10 KW pull-up resistor on this pin. Special test mode is generally used only for factory testing, although there are certain circumstances, such as debugging TPU microcode, in which a limited subset of test mode capabilities are available to users. Driving this pin to approximately 1.6 times VDD causes the MCU to place all output drivers in a high-impedance state, isolating the MCU from the rest of the system.