Usb Jtag Module - Xilinx AC701 User Manual

Chapter 1: AC701 Evaluation Board Features

USB JTAG Module

[Figure
JTAG configuration is provided through a Digilent onboard USB-to-JTAG configuration
logic module (U26) where a host computer accesses the AC701 board JTAG chain through
a standard-A plug (host side) to micro-B plug (AC701 board side) USB cable.
A 2-mm JTAG header (J4) is also provided in parallel for access by Xilinx download cables
such as the Platform Cable USB II and the Parallel Cable IV.
The JTAG chain of the AC701 board is illustrated in
allowed at any time regardless of FPGA mode pin settings. JTAG initiated configuration
takes priority over the configuration method selected through the FPGA mode pin settings
at SW1.
X-Ref Target - Figure 1-8
USB
Module
(U26)
or
JTAG
Connector
(J4)
TDO
TDI
When an FMC card is attached to the AC701 board, it is automatically added to the JTAG
chain through electronically controlled single-pole single-throw (SPST) switch U27. The
SPST switch is in a normally closed state and transitions to an open state when an FMC
card is attached. Switch U27 adds an attached FMC HPC mezzanine card to the FPGAs
JTAG chain as determined by the FMC_HPC_PRSNT_M2C_B signal. The attached FMC
card must implement a TDI-to-TDO connection through a device or bypass jumper in
order for the JTAG chain to be completed to the FPGA U1.
22
Send Feedback
1-2, callout 5]
SPST Bus Switch
U27
J30
FMC HPC
Connector
Part of U19
BUFFER TDI TDO
Figure 1-8: JTAG Chain Block Diagram
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Figure
N.C.
Part of U19
BUFFER
1-8. JTAG configuration is
U1
FPGA
TDI
TDO
UG952_c1_08_012913
AC701 Evaluation Board
UG952 (v1.3) April 7, 2015