I'm currently having trouble to access memory through Nexus while being in debug mode. When the ECU is running the Nexus RW access works as expected. (The µC is a MPC5775K)
Here is my routine:
Go to State: Test-Logic-Reset
Go to State: Run-Test-Idle via Pause-DR (JTAGC regains control of TAP)
Shift-IR: 0x1A (Access Aux OnCE)
Shift-IR: 0x3FF (verify Status register: I'm getting 0x209 as expected)
Then I'm following this example (Example JTAG access – Addendum to application notes AN3283 and AN4365 ) to access Nexus RW, at first everything works normal, but when I'm reading RWCS at last step of the write access I'm getting 0x50000006, which means accroding to table 14-25 in the reference manual that 'Read/Write Access error has occured'. An when I'm then doing the read access I'm not getting 0xDEADBEEF but 0x00000000. And the RWCS is 0x10000006, which agains means 'Read/Write Access error has occured'.