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AR# 17451

3.2 EDK SP2 - XMD does not connect to MDM if an unknown device exists in JTAG chain


Keywords: XMD, MDM, JTAG, unknown, connect

Urgency: Standard

General Description:
When I try to connect from XMD to the MDM debug module, the following message occurs:

"XMD% mbconnect mdm

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
Exiting MDM communication
Unable to connect to JTAG MDM"


In earlier versions (EDK_cm.19 and earlier), if XMD could not determine a device in the JTAG chain, it would designate it as"UNKNOWN" and assign it a default "irlength" value of five. With EDK3.2, this default value is removed and options to specify the JTAG chain are implemented. The options you can use to set the JTAG chain are the same as for the PowerPC.

To work around this issue, use "mbconnect" with the "-configdevice" option for the "UNKNOWN" device. To use the "configdevice" option, use the following arguments:

-configdevice devicenr partname irlength

devicenr = number of devices in JTAG chain to be configured
partname = part name of device
irlength = JTAG instruction register length for device specified in "devicenr"

Use the following for the Insight 2v1000 board with the P160 module in which the CoolRunner device is designated as "UNKNOWN":

mbconnect mdm -configdevice devicenr 3 partname coolrunner irlength 5
AR# 17451
Date Created 06/16/2003
Last Updated 04/06/2007
Status Archive
Type General Article