SCANPSC110FSC Datasheet SCANPSC110FSC, SCANPSC110FSCX | P4-P6

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SCANPSC110F

Overview of SCANPSC110F Bridge Functions

FIGURE 1. SCANPSC110F Bridge Architecture

SCANPSC110F BRIDGE ARCHITECTURE

Figure 1 shows the basic architecture of the

SCANPSC110F. The device’s major functional blocks are

illustrated here. The TAP Controller, a 16-state state

machine, is the central control for the device. The instruc-

tion register and various test data registers can be scanned

to exercise the various functions of the SCANPSC110F

(these registers behave as defined in IEEE Std. 1149.1).

The SCANPSC110F selection controller provides the func-

tionality that allows the 1149.1 protocol to be used in a

multi-drop environment. It primarily compares the address

input to the slot identification and enables the

SCANPSC110F for subsequent scan operations.

The Local Scan Port Network (LSPN) contains multiplexing

logic used to select different port configurations. The LSPN

control block contains the Local Scan Port Controllers

(LSPC) for each Local Scan Port (LSP

, LSP

, and LSP

This control block receives input from the SCANPSC110F

instruction register, mode register, and the TAP controller.

Each local port contains all four (4) boundary scan signals

needed to interface with the local TAPs.

SCANPSC110F BRIDGE STATE MACHINES

The SCANPSC110F is IEEE 1149.1-compatible, in that it

supports all required 1149.1 operations. In addition, it sup-

ports a higher level of protocol, (Level 1), that extends the

IEEE 1149.1 Std. to a multi-drop environment.

In multi-drop scan systems, a scan tester can select indi-

vidual SCANPSC110Fs for participation in upcoming scan

operations. SCANPSC110F “selection” is accomplished by

simultaneously scanning a device address out to multiple

SCANPSC110Fs. Through an on-chip address matching

process, only those SCANPSC110Fs whose statically-

assigned address matches the scanned-out address

become selected to receive further instructions from the

scan tester. SCANPSC110F selection is done using a

“Level-1” protocol, while follow-on instructions are sent to

selected SCANPSC110Fs by using a “Level-2” protocol.

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SCANPSC110F

Overview of SCANPSC110F Bridge Functions (Continued)

FIGURE 2. SCANPSC110F Bridge State Machines

The SCANPSC110F contains three distinct but coupled

state-machines (see Figure 2). The first of these is the

TAP-control state-machine, which is used to drive the

SCANPSC110Fs scan ports in conformance with the

1149.1 Standard (see Figure 17 of appendix). The second

is the SCANPSC110F-selection state-machine (Figure 3).

The third state-machine actually consists of three identical

but independent state-machines (see Figure 4), one per

SCANPSC110F local scan port. Each of these scan port-

selection state-machines allows individual local ports to be

inserted into and removed from the SCANPSC110Fs over-

all scan chain.

The SCANPSC110F selection state-machine performs the

address matching which gives the SCANPSC110F its

multi-drop capability. That logic supports single-

SCANPSC110F access, multi-cast, and broadcast. The

SCANPSC110F-selection state-machine implements the

chip’s Level-1 protocol.

KEY

+ = OR

& = AND

ADDR = 6-bit address in the Instruction Register

SLOT = Static address in the SCANPSC110F Selection Controller

FIGURE 3. State Machine for SCANPSC110F Bridge Selection Controller

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SCANPSC110F

Overview of SCANPSC110F Bridge Functions (Continued)

FIGURE 4. Local SCANPSC110F Bridge Port Configuration State Machine

The SCANPSC110F’s scan port-configuration state-

machine is used to control the insertion of local scan ports

into the overall scan chain, or the isolation of local ports

from the chain. From the perspective of a system’s (single)

scan controller, each SCANPSC110F presents only one

scan chain to the master. The SCANPSC110F architecture

allows one or more of the SCANPSC110F’s local ports to

be included in the active scan chain.

Each local port can be “parked” in one of four stable states

(Parked-TLR, Parked-RTI, Parked-Pause-DR or Parked-

Pause-IR), either individually or simultaneously with other

local ports. Parking a chain removes that local chain from

the active scan chain. Conversely, a parked chain can be

“unparked”, causing the corresponding local port to be

inserted into the active scan chain.

As shown in Figure 4, the SCANPSC110F's three scan

port-configuration state-machines allow each of the part's

local ports to occupy a different state at any given time. For

example, some ports may be parked, perhaps in different

states, while other ports participate in scan operations. The

state-diagram shows that some state transitions depend on

the current state of the TAP-control state-machine. As an

example, a local port which is presently in the Parked-RTI

state does not become unparked (i.e., enter the Unparked

state) until the SCANPSC110F receives an UNPARK

instruction and the SCANPSC110F's TAP state-machine

enters the Run-Test/Idle state.

Similarly, certain transitions of the scan port-configuration

state-machine can force the SCANPSC110F's TAP-control

state-machine into specific states. For example, when a

local port is in the Unparked state and the SCANPSC110F

receives a PARKRTI instruction, the Local Port controller

enters the Parked-RTI state in which TMS

will be held

LOW until the port is later unparked. While TMS

is held

LOW, all devices on that local scan chain remain in their

current TAP State (the RTI TAP controller state in this

example).

The SCANPSC110F's scan port-configuration state-

machine implements part of the SCANPSC110F's Level-2

protocol. In addition, the SCANPSC110F provides a num-

ber of Level-2 instructions for functions other than local

scan port configuration. These instructions provide access

to and control of various registers within the

SCANPSC110F. This set instructions includes:

Figure 5 illustrates how the SCANPSC110F's state-

machines interact. The SCANPSC110F-selection state-

machine enables or disables operation of the chip's three

port-selection state-machines. In SCANPSC110Fs which

are selected via Level-1 protocol (either as individual

SCANPSC110Fs or as members of broadcast or multi-cast

groups), Level-2 protocol commands can be used to park

or unpark local scan ports. Note that most transitions of the

port-configuration state-machines are gated by particular

states of the SCANPSC110F's TAP-control state-machine,

as shown in Figures 4, 5.

BYPASS CNTRSEL

EXTEST LFSRON

SAMPLE/PRELOAD LFSROFF

IDCODE CNTRON

MODESEL CNTROFF

MCGRSEL GOTOWAIT

LFSRSEL

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SCANPSC110FSC

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SCANPSC110FSC

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