AT697F_14 datasheet(74/176 Pages) ATMEL

74 / 176 page

AT697F

7703E–AERO–08/11

JTAG Interface

Overview

The AT697 implements a standard interface compliant with the IEEE 1149.1 JTAG

specification. This interface can be used for PCB testing using the JTAG boundary-scan

capability.

The JTAG interface is accessed through five dedicated pins. In JTAG terminology,

these pins constitute the Test Access Port (TAP).

The following table summarizes the TAP pins and there function at JTAG level.

Table 19. TAP Pins

TCK

Test Clock

Input

Used to clock serial data boundary into scan latches and

control sequence of the test state machine. TCK can be

asynchronous with CLK

TMS

Test Mode select

Input

Primary control signal for the state machine.

Synchronous with TCK. A sequence of values on TMS

adjusts the current state of the TAP.

TDI

Test Data Input

Input

Serial input data to the boundary scan latches.

Synchronous with TCK

TDO

Test Data Output

Output

Serial output data from the boundary scan latches.

Synchronous with TCK

TRST*

Test Reset

Input

Resets the test state machine. can be asynchronous with

TCK

For more details, please refer to the ‘IEEE Standard Test Access Port and Boundary

Scan’ specification.

Any AT697F based system will contain several JTAG compatible chips. These are con-

nected using the minimum (single TMS signal) configuration. This configuration contains

three broadcast signals (TMS, TCK, and TRST*,) which are fed from the JTAG master to

all JTAG slaves in parallel, and a serial path formed by a daisy-chain connection of the

serial test data pins (TDI and TDO) of all slaves.

The TAP supports a BYPASS instruction which places a minimum shift path (1 bit)

between the chip’s TDI and TDO pins. This allows efficient access to any single chip in

the daisy-chain without board-level multiplexing.

Figure 43. JTAG Serial connection using 1 TMS Signal

TDI

TDO

TMS TCK

TRST

TDI

TDO

TMS TCK

TRST

TDI

TDO

TMS TCK

TRST

TDI

TDO

TMS TCK

TRST

TDI

TMS

TCK

TRST

TDO

Part 1

Part 2

Part 3

Part n

Name

Type

Description

AT697F Datasheet(PDF) 74 Page - ATMEL Corporation

AT697F Datasheet(HTML) 74 Page - ATMEL Corporation

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