In case you don’t have it already, please download our AN5238 ‘FS6500 and FS4500 Safe System Basis Chip Hardware Design and Product Guidelines’.
This user guide will help you a lot with detailed guidelines.
Debug pin voltage must be between 2.8V and 4.35V when device powers up:
Below recommended HW connection from AN5238 p.28 (5.8 FS6500 and FS4500 Debug pin):
• DBG_COUT = 10 to 22nF
• DBG_RPD = 11kΩ
• DBG_RPU = 10kΩ
both are necessary
Debug mode is detected at ‘FS select pin config’ phase during power up sequence (Figure 53. Start-up scheme in datasheet).
If debug pin voltage changes after this phase, it will not impact debug mode entry/exit.
To exit debug mode, debug pin voltage must be < 2.1V before powering up again the device.
we hope it helps