We have encountered four defective products about ADSP-21571CSWZ not working, and there are two kinds of defective phenomena：
Symptom 1: No Log is printed, and the Debug port cannot be connected.（A total of 1 PCS ）Phenomenon during debugging: measuring DSP minimum system, RST and power supply are normal, crystal signal is abnormal; When the crystal oscillator is adjusted to the normal board, the phenomenon remains unchanged; When the DSP chip is adjusted to the normal board, both boards work normally. When the normal board and the bad board are switched back to DSP and BA, both boards still work normally.
- Symptom 2: No Log is printed, and you can access the external flash through the Debug port.（A total of 3 PCS）Phenomenon during debugging: 1V1 and 3V3 power supply voltage measurement is normal, crystal vibration is normal, Reset signal is normal; DSP does not send chip selection signal to external Flash; When the DSP chip is adjusted to the normal board, the phenomenon follows the DSP; The BA switch is being made;
May I ask the cause of the above fault? And how to fix it? Thanks a million.