I'm using MPC5606B and I would like to know what kind of issues I would have, concerning protection\encryption if I tried to read its flash content by JTAG by meand of an external device ?
By default there is no protection. Device is unlocked.
There is possibility to enable censorship protection on micro.
This is described in reference manual:
Censorship can be enabled to protect the contents of the flash memory from being read or modified. In order to achieve this, the censorship mechanism controls access to the:• JTAG / Nexus debug interface• Serial boot mode (which could otherwise be used to download and execute code to query or modify the flash memory)
Please refer to chapter 5.1.3 Censorship in reference manual for more details.
I read Chapter 5 in reference manual, it was a very good advise, thank you very much. I understood better how the censorship works but I still have some doubts.
I was able to read the MPC's flash content using a tool (UPA) and a PC, however, I want to do it by my own, using my own embedded hardware without the PC's tool. So, I studied about JTAG standard( JTAG_IEEE-Std-1149.1-2001 ), and about TAP controller state diagram. In order to better understand the JTAG reading, I Used the PC's tool to read the MCP's flash and an osciloscope to see how the communication is performed between the tool and MCP5606B.
I could see that it enters in the TAP controller state machine, The tool writes IR ( 0b0000100011 )and after that reads DR ( 0x2AE4301D ) and there is a lot of more communication that I didn't recognize yet, but, I know that, according to this document, the readed value 0x2AE4301D is the IDCODE of JTAG's MCP5606B.
After to study Chapter five of MPC5606's reference manual, I expected that the tool would send a 64-bits password, but I didn't found it in communication yet ( the time of communication is too big, almost 10s ).
So I was wondering, how, effectively speaking, is performed the reading of the flash memory content, and how it is related to Censorship at bootloader?
Retrieving data ...