6.1.5 State Transitions

Clicking the SAFE to DIAGNOSTIC button makes the device go from the SAFE state to the DIAGNOSTIC state. This transition is done by writing the SAFE_EXIT register with 0x55 and the MASK_DIAG_EXIT register with 0x55.

Clicking the DIAGNOSTIC to ACTIVE button makes the device go from the DIAGNOSTIC state to the ACTIVE state. This transition is done by writing the CLR_CTRL_LOCK register with 0xAA and setting the DIAG_EXIT bit to 1b (writing the SAFETY_CHECK_CTRL register with 0x1).

Before the device goes from the SAFE state to the DIAGNOSTIC or from the DIAGNOSTIC state to the ACTIVE state, the watchdog must be configured correctly. Without configuring the watchdog, the WD Fail Count field increases to 15 which puts the device back in the SAFE state.