B.1.1. Debug scan chains

The two scan paths used for debug purposes are referred to as scan chain 1 and scan chain 2, and are shown in Figure B.1.

Figure B.1. Debug block diagram

Scan chain 1

Scan chain 1 is used for debugging the ARM7EJ-S processor when it has entered debug state. You can use it to:

  • inject instructions into the processor pipeline

  • read and write its registers

  • perform memory accesses.

Scan chain 2

Scan chain 2 enables access to the EmbeddedICE-RT registers. Refer to Test data registers for details.

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