No Nexus RW access in debug mode

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No Nexus RW access in debug mode

Contributor II


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:

  1. Go to State: Test-Logic-Reset
  2. Go to State: Run-Test-Idle via Pause-DR (JTAGC regains control of TAP)
  3. Shift-IR: 0x1A (Access Aux OnCE)
  4. Reset: '0'
  5. Shift-IR: 0x12
  6. Shift-DR: 0x00000005
  7. Reset '1'
  8. Shift-IR: 0x3FF (verify Status register: I'm getting 0x209 as expected)
  9. 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'.

Maybe someone can help me with this problem?

Thanks in advance and regards 


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