Other Parts Discussed in Thread: LM1117
Hi Team,
My customer are using F280049 for three phase OBC control, five pwms output is low, but one pwm is continual high, there will have occasionally that F280049 fail to run, the external oscillator waveform is abnormal, 3.3V and 1.2V output have a lot of noise as below:
After warm reset F28004x by hand, the external oscillator waveform, 3.3V and 1.2V output are normal
After warm reset F28004x by hand, the external oscillator waveform, 3.3V and 1.2V output are normal.
We guess this issue was cause by missing clock, Customer configure TZ5 to shut down all pwm when clock fail, and also configure NMI interrupt to shut down pwms. Also they configure watchdog, but apparently the watchdog did not work. there are two things that hard to explain:
1. Why there still have one pwm output high when configure TZ5 to shut down all pwm? This function have been verify in the lab by disconnecting external clock and all pwms output are low.
2. What cause the external oscillator waveform abnormal, and 3.3V and 1.2V output have a lot of noise? The 3.3V is provide by LM1117, As it is not easy to reproduce this issue, in normal running condition, customer did the test that by adding additional 500mA resistor load for LM1117, the 3.3V and 1.2V output is normal without noise.
Customer used to try F280049 internal clock, but still have possibility that F280049 fail to run. We help review customer schematic, there is no over voltage design on ADC and GPIO pins, and the VDDA, VDD, VDDIO, Reset pin are connected according to datasheet recommendation. Any suggestion for customer to avoid this issue?
