EP2C5T144I8N Datasheet, PDF (440/470 Pages) Altera Corporation – Cyclone II Device Handbook, Volume 1

IEEE Std. 1149.1 BST Operation Control
Figure 14–12. BYPASS Shift Data Register Waveforms
TCK
TMS
TDI
TDO
Bit 1 Bit 2 Bit 3
Bit 1 Bit 2
Bit 4
SHIFT_IR
SHIFT_DR
TAP_STATE
EXIT1_IR SELECT_DR_SCAN
Data shifted into TDI on
Instruction Code ^UPDATE_IR
CAPTURE_DR the rising edge of TCK is
shifted out of TDO on the
falling edge of the same
TCK pulse.
EXIT1_DR
UPDATE_DR
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. The IDCODE for
Cyclone II devices are listed in the Configuration & Testing chapter in
Volume 1 of the Cyclone II 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. The UES value is not
user defined until after the device has been configured. Before
configuration, the UES value is set to the default value.
CLAMP Instruction Mode
The CLAMP instruction mode is used to allow the boundary-scan register
to determine the state of the signals driven from the pins. In CLAMP
instruction mode, the bypass register is selected as the serial path
between the TDI and TDO ports.
14–14
Cyclone II Device Handbook, Volume 1
Altera Corporation
February 2007