Titanium Interfaces User Guide
Chapter 8
JTAG User TAP Interface
Contents:
• JTAG Mode
• Using the JTAG User TAP Block
• Design Check: JTAG User Tap Errors and Warnings
Titanium FPGAs have dedicated JTAG pins to support configuration and boundary scan
testing.
JTAG Mode
The JTAG serial configuration mode is popular for prototyping and board testing. The four-
pin JTAG boundary-scan interface is commonly available on board testers and debugging
hardware.
Efinix FPGAs support IEEE standard 1149.1 - 2001.
Learn more: Refer to the following web sites for more information about the JTAG interface:
http://ieeexplore.ieee.org/document/6515989/
https://en.wikipedia.org/wiki/JTAG
Table 47: Supported JTAG Instructions
Instruction Binary
Code [4:0]
Description
BYPASS 11111 Enables BYPASS.
DEVICE_STATUS 01100 Lets you read the device configuration status.
EFUSE_PREWRITE 11000 Loads user data for fuse operations.
EFUSE_USER_WRITE 11010 Blows fuses as defined in EFUSE_PREWRITE.
EFUSE_WRITE_STATUS 11011 Returns status of EFUSE_USER_WRITE operation.
ENTERUSER 00111 Changes the FPGA into user mode.
EXTEST 00000 Enables the boundary-scan EXTEST operation.
IDCODE 00011 Enables shifting out the IDCODE.
INTEST 00001 Enables the boundary-scan INTEST operation.
JTAG_USER1 01000 Connects the JTAG User TAP 1.
JTAG_USER2 01001 Connects the JTAG User TAP 2.
JTAG_USER3 01010 Connects the JTAG User TAP 3.
JTAG_USER4 01011 Connects the JTAG User TAP 4.
PROGRAM 00100 JTAG configuration.
SAMPLE/PRELOAD 00010 Enables the boundary-scan SAMPLE/PRELOAD
operation.
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