4.6.2. Address and data selection

You can use choose what information is output for each data access, to reduce the bandwidth of the data trace. The following three modes of operation are available:

Address only

Broadcasts only the address of the transfer, or the first address in the case of a load/store multiple. This approach is useful when checking the code to ensure that the correct address is generated for all transfers.

Data value only

Broadcasts only the data value of the transfer.

This approach is useful when there is a high degree of confidence that the address of the transfers is generated correctly, and the address of a transfer can easily be inferred by looking at the instruction that caused the access. For example, if the instruction is located in a section of code for the UART mode control you can assume that the address is that of the UART control register.

Address and data value

The address and data value option outputs both the address and data value of the transfer. This ensures that all information about the transfer is known. However, it requires a larger overall bandwidth through the trace port than the address-only or data-only options.

Because of the techniques used to decompress the trace information after it is captured, you must select a single mode of operation to apply to all data transfers. This means, for example, that in a single trace it is not possible to provide the address only for some transfers and data value only for others.

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