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MPC5775K's secure problem

Question asked by xiao liu on Dec 18, 2016
Latest reply on Dec 29, 2016 by Peter Vlna

Hello,experts,

Recently,I am using the MPC5775K now .To prevent unauthorized people operating flash ,I want to change the password.From the manual MPC5775KRM_Rev3.4,I think to add DCF record can make it.

Relevant instructions are NVSCI recordNVPWDH DCF record and NVPWDL DCF record.

 

 

From the manual ,if configure Censorship Control 0x55AAthe microcontroller will go to censor mode,!55AA will go to uncensor mode.If the microcontroller went to censor mode,it need input private password to operate the microcontroller.

So I did some test use 3 microcontroller.

 

Step 1:microcontroller 1,write NVPWDH DCF record and NVPWDL DCF record in Utest Flash to update password,then I found I Couldn’t connect the Emulator,neither the old password nor the new password ;

 

Step2: microcontroller 2,write NVSCI recordNVPWDH DCF record and NVPWDL DCF record in Utest Flash to update password, configure Censorship Control !0x55AAthe microcontroller will go to uncensored mode,I found no password could connect the Emulator now,but I changed to censor mode,it didn’t work,the microcontroller still need no password.

 

Step3: microcontroller 3,write NVSCI recordNVPWDH DCF record and NVPWDL DCF record in Utest Flash to update password, configure Censorship Control 0x55AAthe microcontroller will go to censored mode,I found only new password could connect the Emulator.And I changed the password again, the microcontroller couldn’t connect the Emulator in any password.

 

So I have 3 questions,

Q1:should NVSCI recordNVPWDH DCF record and NVPWDL DCF record write at the same time to change the password?Can I do thing to microcontroller1 and 3 now?

Q2: From the step 2,is microcontroller’s censored or uncensored mode can be set only once?

Q3: From the step4,is microcontroller’s private password can be set only once?

 

Best regards!!!!!

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