Hardware Description

 

 

Table 3-25 JTAG related signals (continued)

 

 

 

Name

Description

Function

 

 

 

DBGACK

Debug acknowledge

DBGACK indicates to the debugger that the processor core has

 

(to JTAG equipment)

entered debug mode. It is provided for compatibility with

 

 

third-party JTAG equipment.

 

 

 

GLOBAL_DONE

FPGA configured

GLOBAL_DONE is an open-collector signal that indicates when

 

 

FPGA configuration is complete. Although this signal is not a JTAG

 

 

signal, it does affect nSRST. The GLOBAL_DONE signal is

 

 

routed between all RealView boards.

 

 

 

nRTCKEN

Return TCK enable

nRTCKEN is an active LOW signal driven by any tile that requires

 

 

RTCK to be routed back to the JTAG equipment. If nRTCKEN is

 

 

HIGH, the baseboard drives RTCK LOW. If nRTCKEN is LOW,

 

 

the baseboard drives the TCK signal back to the JTAG equipment.

 

 

 

The JTAG path chosen depends on whether the system is in configuration mode or debug mode. The CONFIG link controls the nCFGEN signal that is routed through the PB926EJ-S and tile connectors. Figure 3-43 on page 3-101, Figure 3-44 on page 3-102, and Figure 3-45 on page 3-103 show the JTAG signal routing.

3-100

Copyright © 2003-2010 ARM Limited. All rights reserved.

ARM DUI 0224I

Page 162
Image 162
ARM ARM DUI 0224I manual Dbgack, Nrtcken