PRELIMINARY
PM4318 OCTLIU
DATASHEET
PMC- 2001578
ISSUE 3
OCTAL E1/T1/J1 LINE INTERFACE DEVICE
Boundary Scan Instructions
The following is a description of the standard instructions. Each instruction selects a 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 placed 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 of
the output, TDO, using the Shift-DR state.
Boundary Scan Cells
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 in the JTAG Test Port section 11.2.
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
207
PMC [ PMC-SIERRA, INC ]
