EP3SE50F780I3N Altera, EP3SE50F780I3N Datasheet - Page 452

• Manufacturer Part Number: EP3SE50F780I3N
• Description: Stratix III
• Manufacturer: Altera

IEEE Std. 1149.1 BST Operation Control
Figure 13–9. SAMPLE/PRELOAD Shift Data Register Waveforms
13–14
Stratix III Device Handbook, Volume 1
TAP_STATE
TMS
TDO
TCK
TDI
SHIFT_IR
Instruction Code
During the capture phase, multiplexers preceding the capture registers
select the active device data signals. This data is then clocked into the
capture registers. The multiplexers at the outputs of the update registers
also select active device data to prevent functional interruptions to the
device. During the shift phase, the boundary-scan shift register is formed
by clocking data through the capture registers around the device
periphery and then out of the TDO pin. The device can simultaneously
shift new test data into TDI and replace the contents of the capture
registers. During the update phase, data in the capture registers is
transferred to the update registers. You can then use this data in the
EXTEST instruction mode. Refer to
page 13–14
Figure 13–9
SAMPLE/PRELOAD instruction code is shifted in through the TDI pin. The
TAP controller advances to the CAPTURE_DR state and then to the
SHIFT_DR state, where it remains if TMS is held low. The data that was
present in the capture registers after the capture phase is shifted out of the
TDO pin. New test data shifted into the TDI pin appears at the TDO pin
after being clocked through the entire boundary-scan register. If TMS is
held high on two consecutive TCK clock cycles, the TAP controller
advances to the UPDATE_DR state for the update phase.
EXTEST Instruction Mode
Use the EXTEST instruction mode primarily to check external pin
connections between devices. Unlike the SAMPLE/PRELOAD mode,
EXTEST allows test data to be forced onto the pin signals. By forcing
known logic high and low levels on output pins, you can detect opens
and shorts at pins of any device in the scan chain.
EXIT1_IR
UPDATE_IR
SELECT_DR
for more information.
shows the SAMPLE/PRELOAD waveforms. The
CAPTURE_DR
Data stored in
boundary-scan
register is shifted
out of TDO.
“EXTEST Instruction Mode” on
After boundary-scan
register data has been
shifted out, data
entered into TDI will
shift out of TDO.
SHIFT_DR
Altera Corporation
November 2007
UPDATE_DR
EXIT1_DR