Hardware Description

3.8.1JTAG scan path

Figure 3-11shows a simplified diagram of the scan path.

Core module

Core module

-ICE

 

 

TDO

 

 

 

 

Processor

Multi

 

TDI

TDI

core

 

 

 

 

 

 

 

 

 

 

 

 

HDRB

HDRB

TDI

TDO

nMBDET

Processor

TDI core

HDRB

HDRB

Motherboard

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.

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ARM DUI 0125A