IEEE Std. 1149.1 Boundary-Scan Register
operate the TAP controller, and the TDIand TDOpins provide the serial
path for the data registers. The TDIpin also provides data to the
instruction register, which then generates control logic for the data
registers.
The boundary-scan register is a large serial shift register that uses the TDI
pin as an input and the TDOpin as an output. The boundary-scan register
consists of 3-bit peripheral elements that are associated with Cyclone II
I/O pins. You can use the boundary-scan register to test external pin
connections or to capture internal data.
IEEE Std. 1149.1
Boundary-Scan
Register
f
See the Configuration & Testing chapter in Volume 1 of the Cyclone II
Device Handbook for the Cyclone II device boundary-scan register
lengths.
Figure 14–3 shows how test data is serially shifted around the periphery
of the IEEE Std. 1149.1 device.
Figure 14–3. Boundary-Scan Register
Each peripheral
element is either an
I/O pin, dedicated
input pin, or
Internal Logic
dedicated
configuration pin.
TAP Controller
TDI
TMS
TDO
TCK
Boundary-Scan Cells of a Cyclone II Device I/O Pin
The Cyclone II device 3-bit boundary-scan cell (BSC) consists of a set of
capture registers and a set of update registers. The capture registers can
connect to internal device data via the OUTJand OEJsignals, and connect
14–4
Altera Corporation
Cyclone II Device Handbook, Volume 1
February 2007
ALTERA [ ALTERA CORPORATION ]
