Specifications

DescriptionInstruction CodeJTAG Instruction
Places the 1-bit bypass register between
the TDI and TDO pins. During normal
device operation, the 1-bit bypass
register allows the BST data to pass
synchronously through the selected
devices to adjacent devices.
11 1111 1111
BYPASS
• Examines the user electronic
signature (UES) within the devices
along a JTAG chain.
•
Selects the 32-bit USERCODE
register and places it between the
TDI and TDO pins to allow serial
shifting of USERCODE out of TDO.
• The UES value is set to default value
before configuration and is only
user-defined after the device is
configured.
00 0000 0111
USERCODE
• Identifies the devices in a JTAG
chain. If you select IDCODE, the
device identification register is
loaded with the 32-bit
vendor-defined identification code.
•
Selects the IDCODE register and
places it between the TDI and TDO
pins to allow serial shifting of
IDCODE out of TDO.
•
IDCODE is the default instruction
at power up and in the
TAP RESET state. Without loading
any instructions, you can go to the
SHIFT_DR state and shift out the
JTAG device ID.
00 0000 0110
IDCODE
• Sets all user I/O pins to an inactive
drive state.
• Places the 1-bit bypass register
between the TDI and TDO pins.
During normal operation, the 1-bit
bypass register allows the BST data
to pass synchronously through the
selected devices to adjacent devices
while tri-stating all I/O pins until a
new JTAG instruction is executed.
• If you are testing the device after
configuration, the programmable
weak pull-up resistor or the bus
hold feature overrides the HIGHZ
value at the pin.
00 0000 1011
HIGHZ
JTAG Boundary-Scan Testing in Cyclone V Devices
Altera Corporation
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CV-52009
Supported JTAG Instruction
9-4
2013.05.06