Cortex-M4; Jtag Debug Port; Table 183. Jtag Debug Port Data Registers - STMicroelectronics RM0365 Reference Manual

Debug support (DBG)
33.6.4

Cortex-M4

The ARM
table mapped on the internal PPB bus at address 0xE00FF000_0xE00FFFFF.
This code is accessible by the JTAG Debug Port (4 to 5 pins) or by the SW Debug Port (two
pins) or by the user software.
33.7

JTAG debug port

A standard JTAG state machine is implemented with a 4-bit instruction register (IR) and five
data registers (for full details, refer to the Cortex-M4
(TRM), for references, please see
IR(3:0)
1111
1110
1010
1045/1080
®
F JEDEC-106 ID code
® ®
Cortex-M4 F integrates a JEDEC-106 ID code. It is located in the 4KB ROM

Table 183. JTAG debug port data registers

Data register
BYPASS
[1 bit]
IDCODE ID CODE
[32 bits] 0x3BA00477 (ARM
Debug port access register
This initiates a debug port and allows access to a debug port register.
– When transferring data IN:
Bits 34:3 = DATA[31:0] = 32-bit data to transfer for a write request
Bits 2:1 = A[3:2] = 2-bit address of a debug port register.
Bit 0 = RnW = Read request (1) or write request (0).
DPACC
– When transferring data OUT:
[35 bits]
Bits 34:3 = DATA[31:0] = 32-bit data which is read following a read
request
Bits 2:0 = ACK[2:0] = 3-bit Acknowledge:
010 = OK/FAULT
001 = WAIT
OTHER = reserved
Refer to
DocID025202 Rev 7
®
Fr0p1 Technical Reference Manual
Section 33.2: Reference ARM®
® ®
Cortex-M4
Table 184 for a description of the A(3:2) bits
documentation).
Details
F r0p1 ID Code)
RM0365