ep3c120f780c8nes Altera Corporation, ep3c120f780c8nes Datasheet - Page 388

• Manufacturer Part Number: ep3c120f780c8nes
• Description: Cyclone Iii Device Family
• Manufacturer: Altera Corporation

IEEE 1149.1 (JTAG) Boundary-Scan Testing for Cyclone III Devices
Figure 14–9. SAMPLE/PRELOAD Shift Data Register Waveforms
14–14
Cyclone 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 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. This data can then be used in the EXTEST instruction mode.
Refer to the
Figure 14–9
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.
EXIT1_IR
EXTEST Instruction Mode
The EXTEST instruction mode is used 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, opens and shorts can be
detected at pins of any device in the scan chain.
UPDATE_IR
SELECT_DR
“EXTEST Instruction
shows the SAMPLE/PRELOAD waveforms. The
CAPTURE_DR
Data stored in
boundary-scan
register is shifted
out of TDO.
Mode”section for more information.
Altera Corporation-Preliminary
After boundary-scan
register data has been
shifted out, data
entered into TDI will
shift out of TDO.
SHIFT_DR
March 2007
UPDATE_DR
EXIT1_DR