SC2200 datasheet(356/433 Pages) NSC

356 / 433 page

www.national.com

356

Revision 3.0

7.0

Debugging and Monitoring

7.1

TESTABILITY (JTAG)

The Test Access Port (TAP) allows board level interconnec-

tion verification and chip production tests. An IEEE-

1149.1a compliant test interface, TAP supports all IEEE

mandatory instructions as well as several optional instruc-

tions for added functionality. See Table 7-1 for a summary

of all instructions support. For further information on JTAG,

refer to IEEE Standard 1149.1a-1993 Test Access Port and

Boundary-Scan Architecture.

7.1.1

Mandatory Instruction Support

The TAP supports all IEEE mandatory instructions, includ-

ing:

• BYPASS

Presents the shortest path through a given chip (a 1-bit

shift register).

• EXTEST

Drives data loaded into the JTAG path (possibly with a

SAMPLE/PRELOAD instruction) to output pins.

• SAMPLE/PRELOAD

Captures chip inputs and outputs.

7.1.2

Optional Instruction Support

The TAP supports the following IEEE optional instructions:

• IDCODE

Presents the contents of the Device Identification

• CLAMP

Ensures that the Bypass register is connected between

TDI and TDO, and then drives data that was loaded into

the Boundary Scan register (e.g., via SAMPLE-

PRELOAD instruction) to output signals. These signals

do not change while the CLAMP instruction is selected.

• HIZ

Puts all chip outputs in inactive (floating) state

(including all pins that do not require a TRI-STATE

output for normal functionality). Note that not all pull-up

resistors are disabled in this state.

7.1.3

JTAG Chain

Balls that are not part of the JTAG chain:

• CRT DACs

• USB I/Os

Table 7-1. JTAG Mode Instruction Support

Code

Instruction

Activity

000

EXTEST

Drives shifted data to output pins.

001

SAMPLE/PRELOAD

Captures inputs and system outputs.

010

IDCODE

Scans out device identifier.

011

HIZ

Puts all output and bidirectional pins in TRI-STATE mode.

100

CLAMP

Drives fixed data from Boundary Scan register.

101

Reserved

110

Reserved

111

BYPASS

Presents shortest external path through device.

SC2200 Datasheet(PDF) 356 Page - National Semiconductor (TI)

SC2200 Datasheet(HTML) 356 Page - National Semiconductor (TI)

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL