EP3SL150F780I3N Altera, EP3SL150F780I3N Datasheet - Page 450

• Manufacturer Part Number: EP3SL150F780I3N
• Description: Stratix III
• Manufacturer: Altera

IEEE Std. 1149.1 BST Operation Control
Figure 13–7. Selecting the Instruction Mode
13–12
Stratix III Device Handbook, Volume 1
TAP_STATE
TEST_LOGIC/RESET
TMS
TDO
TCK
TDI
RUN_TEST/IDLE
SELECT_DR_SCAN
The TDO pin is tri-stated in all states except in the SHIFT_IR and
SHIFT_DR states. The TDO pin is activated at the first falling edge of TCK
after entering either of the shift states and is tri-stated at the first falling
edge of TCK after leaving either of the shift states.
When the SHIFT_IR state is activated, TDO is no longer tri-stated, and the
initial state of the instruction register is shifted out on the falling edge of
TCK. TDO continues to shift out the contents of the instruction register as
long as the SHIFT_IR state is active. The TAP controller remains in the
SHIFT_IR state as long as TMS remains low.
During the SHIFT_IR state, an instruction code is entered by shifting
data on the TDI pin on the rising edge of TCK. The last bit of the
instruction code is clocked at the same time that the next state,
EXIT1_IR, is activated. Set TMS high to activate the EXIT1_IR state.
Once in the EXIT1_IR state, TDO becomes tri-stated again. TDO is always
tri-stated except in the SHIFT_IR and SHIFT_DR states. After an
instruction code is entered correctly, the TAP controller advances to
serially shift test data in one of three modes. The three serially shift test
data instruction modes are discussed in the following sections:
■
■
■
SAMPLE/PRELOAD Instruction Mode
The SAMPLE/PRELOAD instruction mode allows you to take a snapshot of
device data without interrupting normal device operation. However, this
instruction is most often used to preload the test data into the update
registers prior to loading the EXTEST instruction.
capture, shift, and update phases of the SAMPLE/PRELOAD mode.
“SAMPLE/PRELOAD Instruction Mode” on page 13–12
“EXTEST Instruction Mode” on page 13–14
“BYPASS Instruction Mode” on page 13–16
SELECT_IR_SCAN
CAPTURE_IR
SHIFT_IR
Figure 13–8
Altera Corporation
November 2007
EXIT1_IR
shows the