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Table Of Contents
Zynq-7000 AP SoC Technical Reference Manual www.xilinx.com 189
UG585 (v1.11) September 27, 2016
Chapter 6: Boot and Configuration
JTAG Enable/Disable Control
The DAP and TAP controllers are controlled by a few mechanisms.
Cascade versus Independent mode
Enable/disable DAP and TAP controllers
Permanently disable JTAG
The JTAG connections can be enabled and disabled using the devcfg.CTRL [JTAG_CHAIN_DIS] bit. It
is set =
1 to disable JTAG to protect the PL from unwanted JTAG accesses.
The DAP controller is enabled by setting the devcfg.CTRL [DAP_EN] bit =
111. Any other value causes
the DAP controller to be bypassed. This bit is lockable by setting the devcfg.LOCK [DBG_LOCK] bit =
1. Once locked, it can only be unlocked with a POR reset.
X-Ref Target - Figure 6-7
Figure 6-7: PS Cascade and Independent JTAG Chain Diagram
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