Hi all,
I found that the SPNIDEN and SPIDEN signal on the Juno board can be driven by the internal driver (SSC_DBGCFG_STAT register) or the debug authentication register in SCC. However, i cannot find the debug authentication register in SCC described in the board.txt, and also failed to get some information from the manual. I am interested in this two signals and try to understand how the signal works. Currently, i have two questions.
1. How can i modify the debug authentication register in the SCC?
2. If i disabled the SPNIDEN or SPIDEN signal by the SSC_DBGCFG_CLR or the SCC, is it possible for external debuggers like DS-5 and DStream to enable it again?
Thanks for any help and discussion!
Best Regards,
Zhenyu
Hi Zhenyu,
You can modify the contents of the Debug Authentication Register via SCC by adding this line to `board.txt':
`board.txt'
SCC: 0x060 0x0000000F
And increment the number where it says `TOTALSCCS: 13'.
`TOTALSCCS: 13'
The format of the SCC is:
Bit [0]: Global external debug enable (default value: 0x1)Bit [1]: SPIDEN (default value: 0x1)Bit [2]: SPNIDEN (default value: 0x1)Bit [3]: Debug Access Port enable (default value: 0x1)
Regarding your second question: no, as that would obviate the point of the SPIDEN and SPNIDEN signals, which is to configure whether external debuggers are able to debug the Secure world :-)
SPIDEN
SPNIDEN
Thanks so much, Ash!! That makes a lot of sense.
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