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Hardware Description
3-22
© Copyright ARM Limited 1999. All rights reserved.
ARM DUI 0125A
3.8.1 JTAG scan path
Figure 3-11 shows a simplified diagram of the scan path.
Figure 3-11 JTAG scan path (simplified)
When the core module is used as a standalone development system, the JTAG scan path
is routed through the processor core and back to the Multi-ICE connector.
When the core module is attached to a motherboard, either directly or with other core
modules, the TDI signal from the top core module is routed down through the HDRB
connectors to the motherboard. The path is routed back up the stack through the
processor core on each core module, before being returned to the Multi-ICE connector.
The motherboard detect signal nMBDET signal is used to control the routing for a
standalone or an attached core module.
The PLDs and FPGAs are included in the scan chain when the core module is in
configuration mode.
Motherboard
Processor
core
Multi-ICE
TDI
TDI
nMBDET
TDO
HDRB
HDRB
Core module
Processor
core
TDI
TDI
TDO
HDRB
HDRB
Core module