Cyclone Device Handbook, Volume 1
Table 3–1. Cyclone JTAG Instructions (Part 2 of 2)
JTAG Instruction
Instruction Code
Description
00 0000 0111
Selects the 32-bit USERCODE register and places it between the
TDI and TDO pins, allowing the USERCODE to be serially shifted
out of TDO.
USERCODE
00 0000 0110
00 0000 1011
Selects the IDCODE register and places it between TDI and TDO,
allowing the IDCODE to be serially shifted out of TDO.
IDCODE
Places the 1-bit bypass register between the TDI and TDO pins,
which allows the BST data to pass synchronously through selected
devices to adjacent devices during normal device operation, while
tri-stating all of the I/O pins.
HIGHZ(1)
00 0000 1010
Places the 1-bit bypass register between the TDI and TDO pins,
which allows the BST data to pass synchronously through selected
devices to adjacent devices during normal device operation while
holding I/O pins to a state defined by the data in the boundary-scan
register.
CLAMP(1)
ICR instructions
Used when configuring a Cyclone device via the JTAG port with a
MasterBlasterTM or ByteBlasterMVTM download cable, or when
using a Jam File or Jam Byte-Code File via an embedded
processor.
00 0000 0001
00 0000 1101
PULSE_NCONFIG
CONFIG_IO
Emulates pulsing the nCONFIGpin low to trigger reconfiguration
even though the physical pin is unaffected.
Allows configuration of I/O standards through the JTAG chain for
JTAG testing. Can be executed before, after, or during
configuration. Stops configuration if executed during configuration.
Once issued, the CONFIG_IOinstruction will hold nSTATUSlow
to reset the configuration device. nSTATUSis held low until the
device is reconfigured.
SignalTap II
instructions
Monitors internal device operation with the SignalTap II embedded
logic analyzer.
Note to Table 3–1:
(1) Bus hold and weak pull-up resistor features override the high-impedance state of HIGHZ, CLAMP, and EXTEST.
In the Quartus II software, there is an Auto Usercode feature where you
can choose to use the checksum value of a programming file as the JTAG
user code. If selected, the checksum is automatically loaded to the
USERCODE register. Choose Assignments > Device > Device and Pin
Options > General. Turn on Auto Usercode.
3–2
Preliminary
Altera Corporation
January 2007
ALTERA [ ALTERA CORPORATION ]
