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Description
Instruction Code
JTAG Instruction
• 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
• 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 holding the I/O pins to a state
defined by the data in the
boundary-scan register.
• If you are testing the device after
configuration, the programmable
weak pull-up resistor or the bus
hold feature overrides the
CLAMP
value at the pin. The
CLAMP
value is
the value stored in the update
register of the boundary-scan cell
(BSC).
00 0000 1010
CLAMP
Emulates pulsing the
nCONFIG
pin low
to trigger reconfiguration even though
the physical pin is not affected.
00 0000 0001
PULSE_NCONFIG
Allows I/O reconfiguration (after or
during reconfigurations) through the
JTAG ports using I/O configuration
shift register (IOCSR) for JTAG testing.
You can issue the
CONFIG_IO
instruc-
tion only after the
nSTATUS
pin goes
high.
00 0000 1101
CONFIG_IO
Altera Corporation
JTAG Boundary-Scan Testing in Cyclone V Devices
9-5
Supported JTAG Instruction
CV-52009
2014.01.10