Datasheet

SCANSTA111

SNLS060K –AUGUST 2001–REVISED APRIL 2013

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CONNECTION DIAGRAM

Table 1. Glossary

LFSR Linear Feedback Shift Register. When enabled, will generate a 16-bit signature of sampled serial test data.

LSP Local Scan Port. A four signal port that drives a local (i.e. non-backplane) scan chain. (e.g., TCK

, TMS

, TDO

TDI

Local Local is used to describe IEEE Std. 1149.1 compliant scan rings and the SCANSTA111 Test Access Port that

drives them. The term local was adopted from the system test architecture that the 'STA111 will most commonly

be used in; namely, a system test backplane with a 'STA111 on each card driving up to 3 local scan rings per

card. (Each card can contain multiple 'STA111s, with 3 local scan ports per 'STA111.)

Park/Unpark/Unparked Parked, unpark, and unparked, are used to describe the state of the LSP controller and the state of the local TAP

controllers (the local TAP controllers refers to the TAP controllers of the scan components that make up a local

scan ring). Park is also used to describe the action of parking a LSP (transitioning into one of the Parked LSP

controller states). It is important to understand that when a LSP controller is in one of the parked states, TMS

held constant, thereby holding or parking the local TAP controllers in a given state.

TAP Test Access Port as defined by IEEE Std. 1149.1.

Selected/Unselected Selected and Unselected refers to the state of the 'STA111 Selection Controller. A selected 'STA111 has been

properly addressed and is ready to receive Level 2 protocol. Unselected 'STA111s monitor the system test

backplane, but do not accept Level 2 protocol (except for the GOTOWAIT instruction). The data registers and

LSPs of unselected 'STA111s are not accessible from the system test master.

Active Scan Chain The Active Scan Chain refers to the scan chain configuration as seen by the test master at a given moment.

When a 'STA111 is selected with all of its LSPs parked, the active scan chain is the current scan register only.

When a LSP is unparked, the active scan chain becomes: TDI

→ the current 'STA111 register → the local scan

ring registers → a PAD bit → TDO

. Refer to Table 6 for Unparked configurations of the LSP network.

Level 1 Protocol Level 1 is the protocol used to address a 'STA111.

Level 2 Protocol Level 2 is the protocol that is used once a 'STA111 is selected. Level 2 protocol is IEEE Std. 1149.1 compliant

when an individual 'STA111 is selected.

PAD A one bit register that is placed at the end of each local scan port scan-chain. The PAD bit eliminates the prop

delay that would be added by the 'STA111 LSPN logic between TDI

and TDO

(n+1)

or TDO

by buffering and

synchronizing the LSP TDI inputs to the falling edge of TCK

, thus allowing data to be scanned at higher

frequencies without violating setup and hold times.

LSB Least Significant Bit, the right-most position in a register (bit 0).

MSB Most Significant Bit, the left-most position in a register.

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