Specifications

IEEE Std. 1149.1 Boundary-Scan Register
The boundary-scan register is a large serial shift register that uses the TDI pin as an input and the TDO pin
as an output. The boundary-scan register consists of 3-bit peripheral elements that are associated with
Cyclone V I/O pins. You can use the boundary-scan register to test external pin connections or to capture
internal data.
Figure 9-1: Boundary-Scan Register
This figure shows how test data is serially shifted around the periphery of the IEEE Std. 1149.1 device.
TCKTMSTDI TDO
Internal Logic
TAP Controller
Each peripheral
element is either an
I/O pin, dedicated
input pin, or
dedicated
configuration pin.
Boundary-Scan Cells of a Cyclone V Device I/O Pin
The Cyclone V device 3-bit BSC consists of the following registers:
•
Capture registers—Connect to internal device data through the OUTJ, OEJ, and PIN_IN signals.
•
Update registers—Connect to external data through the PIN_OUT and PIN_OE signals.
The TAP controller generates the global control signals for the IEEE Std. 1149.1 BST registers (shift,
clock, and update) internally. A decode of the instruction register generates the MODE signal.
The data signal path for the boundary-scan register runs from the serial data in (SDI) signal to the serial
data out (SDO) signal. The scan register begins at the TDI pin and ends at the TDO pin of the device.
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JTAG Boundary-Scan Testing in Cyclone V Devices
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9-9
IEEE Std. 1149.1 Boundary-Scan Register
CV-52009
2013.05.06