Signal Descriptions
ARM DDI 0500D
Copyright © 2013-2014 ARM. All rights reserved.
A-25
ID021414
Non-Confidential
A.13
External debug interface
The following sections describe the external debug interface signals:
•
APB interface signals
.
•
Miscellaneous debug signals
.
A.13.1 APB interface signals
Table A-34
shows the APB interface signals.
Note
You must balance all APB interface signals with respect to
CLKIN
and time them relative to
PCLKENDBG
.
A.13.2 Miscellaneous debug signals
Table A-35 on page A-26
shows the miscellaneous Debug signals.
Table A-34 APB interface signals
Signal
Direction
Description
nPRESETDBG
Input
APB reset, active-LOW:
0
Apply reset to APB interface.
1
Do not apply reset to APB interface.
PADDRDBG[21:2]
Input
APB address bus.
PADDRDBG31
Input
APB address bus bit[31]:
0
Not an external debugger access.
1
External debugger access.
PCLKENDBG
Input
APB clock enable.
PENABLEDBG
Input
Indicates the second and subsequent cycles of an APB transfer.
PRDATADBG[31:0]
Output
APB read data.
PREADYDBG
Output
APB slave ready.
An APB slave can deassert
PREADYDBG
to extend a transfer by inserting wait
states.
PSELDBG
Input
Debug bus access.
PSLVERRDBG
Output
APB slave transfer error:
0
No transfer error.
1
Transfer error.
PWDATADBG[31:0]
Input
APB write data.
PWRITEDBG
Input
APB read or write signal:
0
Reads from APB.
1
Writes to APB.