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AR# 18004

6.1 EDK - XMD fails to connect to MicroBlaze if the JTAG chain contains unknown devices


Keywords: XMD, MB, MicroBlaze, mbconnect, GDB, JTAG

Urgency: Standard

General Description:
XMD fails to connect to MicroBlaze if the JTAG chain contains unknown devices or a device is not correctly identified by the tools. For example, the chain contains the following devices:
1. PROM 18V04
2. FPGA v2-1000
3. CPLD xcr3064xl
It seems that the 3rd device (coolrunner) is not identified correctly and XMD fails to connect.
XMD% mbconnect stub

JTAG chain configuration
Device ID Code IR Length Part Name
1 05026093 8 XC18V04
2 01028093 6 XC2V1000
3 0484802b 0 UNKNOWN
Assuming, Device No: 2 contains the MicroBlaze system
JTAG Uart WriteByte timeout. Value = 0xfe. Status = 0x48
Unable to resync with the stub. Sending System Reset signal
JTAG Uart ReadByte timeout. Status = 0x48
No response to Debug_SYS_Rst signal. Unable to sync with stub on board
Unable to establish connection to xmdstub
Unable to connect to MicroBlaze Target


Use the following xmd command line to specify the third or unknown device:

mbconnect stub -configdevice devicenr 3 irlength 5 partname coolrunner

This problem is fixed in the latest 6.1 EDK Service Pack, available at:
The first service pack containing the fix is EDK 6.1 Service Pack 1.
AR# 18004
Date 03/05/2006
Status Archive
Type General Article
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