S/UNI®-JET Data Sheet
Released
The following is an description of the standard instructions. Each instruction selects an serial test
data register path between input, TDI and output, TDO.
BYPASS
The bypass instruction shifts data from input, TDI to output, TDO with one TCK clock period
delay. The instruction is used to bypass the device.
EXTEST
The external test instruction allows testing of the interconnection to other devices. When the
current instruction is the EXTEST instruction, the boundary scan register is place between input,
TDI and output, TDO. Primary device inputs can be sampled by loading the boundary scan
register using the Capture-DR state. The sampled values can then be viewed by shifting the
boundary scan register using the Shift-DR state. Primary device outputs can be controlled by
loading patterns shifted in through input TDI into the boundary scan register using the
Update-DR state.
SAMPLE
The sample instruction samples all the device inputs and outputs. For this instruction, the
boundary scan register is placed between TDI and TDO. Primary device inputs and outputs can
be sampled by loading the boundary scan register using the Capture-DR state. The sampled
values can then be viewed by shifting the boundary scan register using the Shift-DR state.
IDCODE
The identification instruction is used to connect the identification register between TDI and TDO.
The device's identification code can then be shifted out using the Shift-DR state.
STCTEST
The single transport chain instruction is used to test out the TAP controller and the boundary scan
register during production test. When this instruction is the current instruction, the boundary scan
register is connected between TDI and TDO. During the Capture-DR state, the device
identification code is loaded into the boundary scan register. The code can then be shifted out
output, TDO using the Shift-DR state.
Boundary Scan Cell Description
In the following diagrams, CLOCK-DR is equal to TCK when the current controller state is
SHIFT-DR or CAPTURE-DR, and unchanging otherwise. The multiplexer in the center of the
diagram selects one of four inputs, depending on the status of select lines G1 and G2. The ID
Code bit is as listed in the Boundary Scan Register table located in the TEST FEATURES
DESCRIPTION - JTAG Test Port section.
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-1990267, Issue 3
292
PMC [ PMC-SIERRA, INC ]
