Texas Instruments TMDSEMU560V2STM-U - Blackhawk XDS560v2 System Trace USB Emulator TMDSEMU560V2STM-U TMDSEMU560V2STM-U Datenbogen

3-2

There are five standard signals and a ground used for JTAG connections to
control the JTAG

†

 Test Access Port (TAP) Controller, as defined by the IEEE

1149.1 standard.

These signals are shown in Table 3−1.

As a method of confirming a proper connection of the emulation hardware, TI
also uses two other signals provided on the JTAG header (Table 3−2):

-

The Target Voltage Detect signal

-

The Target Disconnect signal

The Target Voltage Detect signal is used to set the I/O voltage of the XDS560
Target pod. The Target Disconnect signal should be tied to ground on the target
board.

† The term JTAG, as used in this book, refers to TI scan-based emulation, which is based on the IEEE 1149.1 standard.

†

‡

TRST

‡

Test Reset

‡

O

I

TMS

Test Mode Select

O

I

TDI

Test Data Input

O

I

TDO

Test Data Output

I

O

TCK

Test Clock (XDS560 POD sourced)

O

I

TCK_RET

Test Clock Return (Buffered or un-buffered connection of
TCK coming back from the target)

I

O

GND

Ground

GND

† I = Input, O = Output
‡ Do not use pullup resistors on TRST: it has an internal pull-down device. In a low-noise environment, TRST can be left floating.

In a high-noise environment, an additional pull-down resistor may be needed. (The size of this resistor should be based on
electrical current considerations.)

†

TVD(V

I/O

)

Target Voltage Detect: TVD should be tied to the I/O Volt-
age of the target processor.

I

O

TDIS

Target Disconnect

I

GND

† I = Input, O = Output