SCANPSC110F datasheet(10/29 Pages) NSC

10 / 29 page

Level 1 Protocol (Continued)

TABLE 4. SCANPSC110F Bridge Address Modes

Address Types

Hex Address

(Note 2)

Binary Address

(Note 3)

TDO

B State

Direct Address

00 to 3A

XX000000 to XX111010

Normal IEEE Std. 1149.1

Broadcast Address

XX111011

Always TRI-STATED

Multi-Cast Group 0

XX111100

Always TRI-STATED

Multi-Cast Group 1

XX111101

Always TRI-STATED

Multi-Cast Group 2

XX111110

Always TRI-STATED

Multi-Cast Group 3

XX111111

Always TRI-STATED

Note 2: Hex address ’7X’, ’BX’, or ’FX’ may be used instead of ’3X’.

Note 3: Only the six (6) LSB’s of the address is compared to the S(0–5) inputs. The two (2) MSB’s are “don’t cares”.

DIRECT ADDRESSING

The ’PSC110F enters the

Wait-For-Address state when:

its TAP Controller enters the

Test-Logic-Reset state, or

its instruction register is updated with the GOTOWAIT in-

struction (while either selected or unselected).

Each ’PSC110F within a scan network must be statically

configured with a unique address via its S

(0–5) inputs. While

the ’PSC110F controller is in the

Wait-For-Address state,

data shifted into bits 5 through 0 of the instruction register is

compared with the address present on the S

(0–5) inputs in

the

Update-IR state. If the six (6) LSBs of the instruction reg-

ister match the address on the S

(0–5) inputs, (see Figure 6 )

the ’PSC110F becomes selected, and is ready to receive

Level 2 Protocol (i.e., further instructions). When the

’PSC110F is selected, its device identification register is in-

serted into the active scan chain.

All ’PSC110Fs whose S

(0–5) address does not match the in-

struction register address become unselected. They will re-

main unselected until either their TAP Controller enters the

Test-Logic-Reset state, or their instruction register is up-

dated with the

GOTOWAIT instruction.

BROADCAST ADDRESSING

The Broadcast Address allows a tester to simultaneously se-

lect all ’PSC110Fs in a test network. This mode is useful in

testing systems which contain multiple identical boards. To

avoid bus contention between scan-path output drivers on

different boards, each ’PSC110F’s TDO

B buffer is always

tri-stated while in Broadcast mode. In this configuration, the

on-chip Linear Feedback Shift Register (LFSR) can be used

to accumulate a test result signature for each board that can

be read back later by direct-addressing each board’s

’PSC110F.

MULTI-CAST ADDRESSING

As a way to make the broadcast mechanism more selective,

the ’PSC110F provides a “Multi-cast” addressing mode. A

’PSC110F’s multi-cast group register (MCGR) can be pro-

grammed to assign that ’PSC110F to one of four (4)

Multi-Cast

groups.

When

’PSC110Fs

the

Wait-For-Address state are updated with a Multi-Cast ad-

dress, all ’PSC110Fs whose MCGR matches the Multi-Cast

group will become selected. As in Broadcast mode, TDO

B is

always tri-stated while in Multi-cast mode.

DS100327-7

FIGURE 6. Direct Addressing: Device Address Loaded into Instruction Register

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