ARM Cortex-M3 Technical Reference Manual page 298

Debug Port
IR contents Description
DPACC Read Buffer
ABORT DAP Abort Register
ABORT -
a. There is no address associated with IDCODE accesses. See Accessing the JTAG-DP registers.
b. The value read on the ABORT scan chain is Unpredictable. The result of accessing the ABORT scan chain with the address
field not set to is Unpredictable
0x0
12.5.2 SW-DP Registers
12-48
Address
0xC
0x0
-
0x4 0xC
Accessing the JTAG-DP registers
The JTAG-DP registers are only accessed when the Instruction Register (IR) for the
DAP access contains the IDCODE, DPACC or ABORT instruction. In detail, the
register accesses for each instruction are:
IDCODE The IDCODE scan chain has no address field, and accesses the IDCODE
register.
DPACC The DPACC scan chain accesses registers at addresses
ABORT For a write access with address
ABORT register.
For a read access with address
, the behavior of the ABORT scan chain is Unpredictable.
0xC
For most register addresses on the SW-DP, different registers are addressed on read and
write accesses. In addition, the CTRLSEL bit in the Select Register changes which
register is accessed at address 0b01.
Copyright © 2005, 2006 ARM Limited. All rights reserved.
Access Reference
RAZ/WI The Read Buffer, RDBUFF on
page 12-59
The Abort Register, ABORT on
b
WO
page 12-49
- -
0x0
, and for any access with address
0x0
Table 12-13 JTAG-DP register map
Notes
-
-
- b
0x0
, the ABORT scan chain accesses the
ARM DDI 0337B
to .
0xC
to
0x4