Atmel ARM-Based Evaluation Kit AT91SAM9N12-EK AT91SAM9N12-EK Fiche De Données
Codes de produits
AT91SAM9N12-EK
Debug Support
11-2
Copyright © 2001-2003 ARM Limited. All rights reserved.
ARM DDI0198D
11.1
About debug support
Debug support is implemented by using the ARM9EJ-S core embedded within the
ARM926EJ-S processor. Full details of the debug support provided by the ARM9EJ-S
core are described in the ARM9EJ-S Technical Reference Manual.
ARM926EJ-S processor. Full details of the debug support provided by the ARM9EJ-S
core are described in the ARM9EJ-S Technical Reference Manual.
Debug support for the ARM926EJ-S memory system is implemented by extending the
debug facilities providing access to CP15 using an ARM9EJ-S external scan chain (scan
chain 15). This scan chain is external to the ARM9EJ-S core but internal to the
ARM926EJ-S processor.
debug facilities providing access to CP15 using an ARM9EJ-S external scan chain (scan
chain 15). This scan chain is external to the ARM9EJ-S core but internal to the
ARM926EJ-S processor.
11.1.1
Debug clocks
The system and test clocks must be synchronized externally to the ARM926EJ-S
macrocell. To synchronize off-chip debug clocking with the ARM926EJ-S macrocell
requires a three-state synchronizer. This is described in the debug chapter of the
ARM9EJ-S Technical Reference Manual.
macrocell. To synchronize off-chip debug clocking with the ARM926EJ-S macrocell
requires a three-state synchronizer. This is described in the debug chapter of the
ARM9EJ-S Technical Reference Manual.
11.1.2
Scan chain 15
Scan chain 15 enables access to the CP15 registers. Scan chain 15 is 48 bits long.
Table 11-1 shows the bit assignments for scan chain 15.
Table 11-1 shows the bit assignments for scan chain 15.
With scan chain 15 selected, TDI is connected to bit 47 and TDO is connected to bit 0.
Table 11-1 Scan chain 15 format
Bits
Function
[47]
Write, not read (W/R)
[46:33]
Register address
[32]
Initiate access/access complete
When written:
1 = initiate new access
0 = NOP
When read:
1 = access complete
0 = access incomplete
When written:
1 = initiate new access
0 = NOP
When read:
1 = access complete
0 = access incomplete
[31:0]
Data value