When I get MPC5744P power-on , power voltage is OK . And EXT_POR_B is high , MDO0 is high , but the RESET_b is low-level all the time . I don't know why it is low all the time. Please help me to analyze this issue, thank you.
MDO0 is copying POR value. If POR is high MDO is also high.
But I suspect here your core voltage. When your core is in reset RESET_b will be low. Upon releasing core reset RESET_b will change to high.
Check your core voltage first.
Hi Peter . thanks a lot for your reply.
the root cause of this issue is found by me . it is caused by the state of EXT_POR_b. I don't set it as High-level. The EXT_POR_b need to be set in the Pull-up mode.
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