SCANSTA111

SNLS060K – AUGUST 2001 – REVISED APRIL 2013

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LEVEL 2 PROTOCOL

Once the SCANSTA111 has been successfully addressed and selected, its internal registers may be accessed

via Level-2 Protocol. Level-2 Protocol is compliant to IEEE Std. 1149.1 TAP protocol with one exception: if the

must be implemented this way to prevent bus contention.) Upon being selected, (i.e., the 'STA111 Selection

controller transitions from the Wait-For-Address state to one of the Selected states), each of the local scan ports

The UNPARK instruction (described later) is used to insert one or more local scan ports into the active scan

chain. Table 6 describes which local ports are inserted into the chain, and in what order.

LEVEL 2 INSTRUCTION TYPES There are two types of instructions (reference Table 4):

1. Instructions that insert a 'STA111 register into the active scan chain so that the register can be captured or

updated

(BYPASS,

SAMPLE/PRELOAD,

EXTEST,

ID-CODE,

MODESEL,

MCGRSEL,

LFSR-SEL,

CNTRSEL).

2. Instructions that configure local ports or control the operation of the linear feedback shift register and counter

registers (UNPARK, PARKTRL, PARKRTI, PARK-PAUSE, GOTOWAIT, SOFTRESET, LFSRON, LFSROFF,

CNTRON, CNTROFF). These instructions, along with any other yet undefined Op-Codes, will cause the

device identification register to be inserted into the active scan chain.

Table 4. Level 2 Protocol and Op-Codes

Instructions

Hex Op-Code

Binary Op-Code

Data Register

BYPASS

FF

1111 1111

Bypass Register

EXTEST

00

0000 0000

Boundary-Scan Register

SAMPLE/PRELOAD

81

1000 0001

Boundary-Scan Register

IDCODE

AA

1010 1010

Device Identification Register

UNPARK

E7

1110 0111

Device Identification Register

PARKTLR

C5

1100 0101

Device Identification Register

PARKRTI

84

1000 0100

Device Identification Register

PARKPAUSE

C6

1100 0110

Device Identification Register

C3

1100 0011

Device Identification Register

MODESEL

8E

1000 1110

82

1000 0010

83

1000 0011

85

1000 0101

MCGRSEL

03

0000 0011

Multi-Cast Group Register

SOFTRESET

88

1000 1000

Device Identification Register

LFSRSEL

C9

1100 1001

Linear Feedback Shift Register

LFSRON

0C

0000 1100

Device Identification Register

LFSROFF

8D

1000 1101

Device Identification Register

CNTRSEL

CE

1100 1110

32-Bit TCK Counter Register

CNTRON

0F

0000 1111

Device Identification Register

CNTROFF

90

1001 0000

Device Identification Register

07

0000 0111

Set Bypass_reg as default data register

TRANSPARENT0

A0

1010 0000

TRANSPARENT1

A1

1010 0001

TRANSPARENT2

A2

1010 0010

TRANSPARENT3

A3

1010 0011

(1)

All other instructions act on selected 'STA111s only.

(2)

Commands added to HDL version of 'STA111.

12

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