User manual

Table Of Contents
Zynq-7000 AP SoC Technical Reference Manual www.xilinx.com 716
UG585 (v1.11) September 27, 2016
Chapter 27: JTAG and DAP Subsystem
PL must be configured to route the trace signal from the EMIO at the PS/PL boundary to the PL
SelectIO.
27.5 ARM DAP Controller
The debug access port (DAP) is an implementation of an ARM debug interface standard comprising
a number of components supplied in a single configuration. All of the supplied components fit into
the various architectural components for debug ports (DPs) which are used to access the DAP from
an external debugger, and access ports (APs) to access on-chip system resources.
With the JTAG-DP, IEEE 1149.1 scan chains are used to read or write register information. A pair of
scan chain registers is used to access the main control and access registers within the debug port:
DPACC used for debug port (DP) accesses
APACC used for access port (AP) accesses
An APACC might access a register of a debug component of the system to which the interface is
connected. The scan chain model implemented by a JTAG-DP has the concepts of capturing the
current value of APACC or DPACC, and of updating APACC or DPACC with a new value. An update
might cause a read or write access to a DAP register that might then cause a read or write access to
a debug register of a connected debug component.
Table 27-2 shows four Tap ARM DAP IR Instructions. All other IR Instructions are implemented as
BYPASS.
X-Ref Target - Figure 27-5
Figure 27-5: User Case II: PS and PL Debug with Trace Port Enabled
DAP TAP
TPIU
JTAG
Xilinx
Platform
Cable
SS
Soft Core
PS
PL
ARM
Review
ICE
SS
ARM
DStream
SS
Soft Core
SRST
JTAG
UG585_c27_05_031812