9.3.3. ETB RAM Read Data Register, RRD, 0x010

When trace capture is disabled, the contents of the ETB Trace RAM at the location addressed by the RAM Read Pointer Registers are placed in this register. Reading this register increments the RAM Read Pointer Register and triggers a RAM access cycle.

If trace capture is enabled (FtStopped=0, TraceCaptEn=1), and ETB RAM reading is attempted, a read from this register outputs 0xFFFFFFFF and the RAM Read Pointer Register does not auto-increment.

A constant stream of 1s being output corresponds to a synchronization output in the formatter protocol, which is not applicable to the ETB, and so can be used to signify a read error, when formatting is enabled.

Table 9.7 shows the ETB RAM Read Data Register bit assignments.

Table 9.7. ETB RAM Read Data Register bit assignments.

BitsTypeNameFunction
[31:0]RORAM Read Data, RRDData read from the ETB Trace RAM.

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