12.1. Slave Operation (Test mode)

When the block is selected as a slave, it is possible to write and read test vectors to the core using the AMBA test methodology.

The BTRAN provides 4 test modes for this purpose:

To apply test vectors to the ARM720T, the ARM720T block must have been deselected as a master (AGNT goes LOW). The Test Interface Controller becomes the bus master, and the ARM720T is selected as a slave using the signal DSELARM. This places the ARM720T into test mode, and allows access to the test registers.

The tests are sequenced by the test state machine in the AMBA interface, which generates the appropriate control signals for the test modes.

A sample test sequence is shown in Figure 12.1.

Figure 12.1. Running a test vector on the processor core

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