ITP700 Debug Port Design Guide

34 ITP700 Debug Port Design Guide

The following tables identify the signals that make up the ITP debug port connector definition.

The I/O direction indicated for each signal is with respect to the debug port. Local TAP refers to a

resident TAP master system that has been installed as part of a system designer’s manufacturing

process. Values of required pull up and pull down resistors are documented in the recommended

termination table in this chapter.

Table 14. ITP700 DPA System Signal Descriptions

Debug Port

Signal

I/O Description

PWR 22 Input System Power. PWR is used for three purposes on the ITP hardware:

To generate the recovery reference voltage for the BPM[5:0]# and

RESET# signals.

To sense if the target has stable power at the debug port.

To arbitrate for the scan chain (in conjunction with DBA#) if a local

TAP master exists. If PWR is asserted (High), the ITP will be allowed

to take and maintain control of the JTAG signals, but if PWR is de-

asserted (pulled low by an open drain on the target), the debug port

output signals will be tristated by the ITP.

BCLK(p/n) 19/21 Input Differentially driven Bus Clock of the target system. Used to sample

execution signals, and to provide a reference for delay align signals

driven from the debug port. When the ITP is operating in synchronous

mode, TCK is delay locked (skewed) to BCLK(p/n).

DBA# 4 Output Debug Port Active. The DBA# signal is an output of the ITP that

indicates that the ITP is using the target system TAP interface. This

signal is optional for ITP implementation. This signal is open drain and

must be provided with a pull-up resistor on the target if this signal is

used.

DBR# 6 Output Debug Port Reset. Open drain signal used to tell the target to initiate

a reset through the reset controller. The ITP can hold this signal Low

for a configurable period or perpetually. This signal is open drain and

must be provided with a pull-up resistor on the target.

FBI 18 Output Alternate source of TAP master clock. FBI is a copy of TCK without

passive edge rate control. When a buffered copy of TCK is required

for routing or level shifting, FBI should be used as the source for the

scan chain TCK. FBI is optional for most ITP implementations since

TCK is generally used as the TAP master clock.

FBO 17 Input FBO is used to register TDO into the ITP tool.