Table 11-28 Bit Functions Of The Ahb-Ap Control And Status Word Register - ARM Cortex-M3 Technical Reference Manual

Field Name
[31:30] -
[29] a
MasterType
[28:26] -
[25] Hprot1
[24] -
[23:12] -
[11:8] Mode
[7] TransINProg
[6] DbgStatus
ARM DDI 0337B
Table 11-28 describes the fields of the AHB-AP Control and Status Word Register.

Table 11-28 Bit functions of the AHB-AP Control and Status Word Register

Definition
Reserved. Read as b010
0 = Core
1 = Debug
This bit cannot be cleared if COREACCEN = 0. Read back to confirm if accepted. It cannot be
changed if transaction is outstanding. (Debugger should first check TransinProg.)
Reset value = 0b1
Reserved, 0b000.
User/Privilege control - HPROT[1]
Reset value = 0b1
Reserved, 0b1.
Reserved, 0x000
Mode of operation bits:
b0000 = normal download/upload mode
b0001-b1111 are reserved.
Reset value = 0b0000.
Transfer in progress. This field indicates if a transfer is in progress on the APB master port.
Indicates the status of the DBGEN port. If DbgStatus is LOW, no AHB transfers carried out.
1 = AHB transfers permitted.
0 = AHB transfers not permitted.
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System Debug
11-37