60.7.11 SECUMOD JTAG Protection Control Register

Note: Reset value is:
  • 0x00000000 when fuse DEFDBG is programmed.
  • 0x00000008 when fuse DEFDBG is not programmed.
Name: SECUMOD_JTAGCR
Offset: 0x0070
Reset: see Note
Property: Read/Write

Bit 3130292827262524 
          
Access  
Reset  
Bit 2322212019181716 
          
Access  
Reset  
Bit 15141312111098 
          
Access  
Reset  
Bit 76543210 
    PROC_DEBUG_MONPROC_DEBUG_MODE[2:0]FNTRST 
Access R/WR/WR/WR/WR/W 
Reset  

Bit 4 – PROC_DEBUG_MON Debug Acknowledge (DBGACK) Monitoring

ValueDescription
0 The Arm processor pin DBGACK is not monitored; as a consequence, the software can access debug features of the processor without causing an intrusion in the SECUMOD.
1 The Arm processor pin DBGACK is monitored. Processor entering in Debug mode triggers an intrusion.

Bits 3:1 – PROC_DEBUG_MODE[2:0] Invasive/Non-Invasive Secure/Non-Secure Debug Permissions

This field is used to set different debug permission levels. For instance, it can be used to prevent debug on secure parts of the code. The table below shows the effect of the field value on the processor pins (SPIDEN, DBGEN, SPNIDEN and NIDEN).

PROC_DEBUG_MODE Value Debug Permissions SPIDEN DBGEN SPNIDEN NIDEN
b000 No Debug 0 0 0 0
b001 Non-Invasive, Non-Secure 0 0 0 1
b010 Full Non-Secure (Invasive and Non-Invasive) 0 1 0 0
b011 Full Non-Secure + Non-Invasive Secure 0 1 1 1
b100 Full Debug allowed 1 1 1 1

Bit 0 – FNTRST Force NTRST

ValueDescription
0 The Arm processor TAP controller access and Boundary JTAG are not blocked by the SECUMOD.
1 nDBGRESET of the Arm processor TAP controller and Boundary JTAG reset are held low, preventing the processor to switch to Debug state and Boundary JTAG to work.