9–16
Altera Corporation
Stratix II Device Handbook, Volume 2
January 2008
IEEE Std. 1149.1 BST Operation Control
Figure 9–12. BYPASS Shift Data Register Waveforms
IDCODE Instruction Mode
The IDCODE instruction mode is used to identify the devices in an IEEE
Std. 1149.1 chain. When IDCODE is selected, the device identification
register is loaded with the 32-bit vendor-defined identification code. The
device ID register is connected between the TDI and TDO ports, and the
device IDCODE is shifted out.
f
For more information on the IDCODE for Stratix II and Stratix II GX
volume 1 of the Stratix II GX Device Handbook.
USERCODE Instruction Mode
The USERCODE instruction mode is used to examine the user electronic
signature (UES) within the devices along an IEEE Std. 1149.1 chain. When
this instruction is selected, the device identification register is connected
between the TDI and TDO ports. The user-defined UES is shifted into the
device ID register in parallel from the 32-bit USERCODE register. The UES
is then shifted out through the device ID register.
1
The UES value is not user defined until after the device is
configured. Before configuration, the UES value is set to the
default value.
Data shifted into TDI on
the rising edge of TCK is
shifted out of TDO on the
falling edge of the same
TCK pulse.
UPDATE_IR
SELECT_DR_SCAN
CAPTURE_DR
EXIT1_IR
EXIT1_DR
UPDATE_DR
SHIFT_DR
Instruction Code
TCK
TMS
TDI
TDO
TAP_STATE
SHIFT_IR
Bit 2
Bit 3
Bit 1
Bit 2
Bit 4
Bit 1
