IEEE Std. 1149.1 (JTAG) Boundary-Scan Support
Table 3–1. MAX II JTAG Instructions (Part 2 of 2)
JTAG Instruction
Instruction Code
Description
USERCODE
00 0000 0111
Selects the 32-bit USERCODEregister and places it between
the TDIand TDOpins, allowing the USERCODEto be serially
shifted out of TDO. This register defaults to all 1’s if not
specified in the Quartus II software.
IDCODE
00 0000 0110
00 0000 1011
Selects the IDCODEregister and places it between TDIand
TDO, allowing the IDCODE to be serially shifted out of TDO.
HIGHZ(1)
Places the 1-bit bypass register between the TDIand TDO
pins, which allows the boundary scan test data to pass
synchronously through selected devices to adjacent devices
during normal device operation, while tri-stating all of the I/O
pins.
CLAMP(1)
00 0000 1010
Places the 1-bit bypass register between the TDIand TDO
pins, which allows the boundary scan test 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.
USER0
USER1
00 0000 1100
00 0000 1110
(2)
This instruction allows you to define the scan chain between
TDIand TDOin the MAX II logic array. This instruction is also
used for custom logic and JTAG interfaces.
This instruction allows you to define the scan chain between
TDIand TDOin the MAX II logic array. This instruction is also
used for custom logic and JTAG interfaces.
IEEE 1532 instructions
IEEE 1532 ISC instructions used when programming a MAX II
device via the JTAG port.
Notes to Table 3–1:
(1) HIGHZ, CLAMP, and EXTESTinstructions do not disable weak pull-up resistors or bus hold features.
(2) These instructions are shown in the 1532 BSDL files, which will be posted on the Altera® website at
www.altera.com when they are available.
w
Unsupported JTAG instructions should not be issued to the
MAX II device as this may put the device into an unknown state,
requiring a power cycle to recover device operation.
3–2
MAX II Device Handbook, Volume 1
Core Version a.b.c variable
Altera Corporation
December 2007
ALTERA [ ALTERA CORPORATION ]
