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Zynq-7000 AP SoC Technical Reference Manual www.xilinx.com 717
UG585 (v1.11) September 27, 2016
Chapter 27: JTAG and DAP Subsystem
The ARM DAP is composed of one debug port (DP) and up to three access ports (APs). Among the
three APs, Zynq-7000 devices only implement APB-AP as the bus master to access all debug
components and AHB-AP to access system memory space directly. Table 27-3 lists all registers within
the DP.
Table 27-4 shows AHB-AP and APB-AP registers in the DAP. For each AP, there is a unique set of
registers associated with each AP port. Although the DAP allows JTAG-AP, Zynq devices do not
support this feature.
Table 27-2: ARM DAP IR Instruction
IR Instruction Binary Code[3:0] DR Width Description
ABORT
1000
35
JTAG-DP abort register
DPACC
1010
35
JTAG DP access register
APACC
1011
35
JTAG-AP access Register
ARM_IDCODE
1110
32
IDCODE for ARM DAP IP
BYPASS
1111
1
Table 27-3: DP Registers Summary
DP Register Access Description
CTRL/STAT IR=DPACC/ADDRESS =
0x4
DP Control and Status register
SELECT IR=DPACC/ADDRESS =
0x8
Its main purpose is to select the current access port and
the active four-word register window in that access port
Table 27-4: AP Registers Summary
AP Register Access Description
CSW IR=APACC/ADDRESS = 0x0 Control and status word
TAR IR=APACC/ADDRESS = 0x4 Transfer address, TAR
DRW IR=APACC/ADDRESS = 0xC Data read/write
BD0-3 IR=APACC/ADDRESS = 0x10 to 0x1C Band data 0 to 3