Table 3-8 Ram Write Pointer Register Bit Allocations; Ram Write Pointer Register, R6 - ARM ETB11 Technical Reference Manual

Programmer's Model

3.2.7

3-8

When read, the RAM Read Pointer Register returns the current trace RAM read address.

You cannot write to this register if TraceCaptEn is HIGH.

This register is not accessible from the AHB interface because the RAM is

memory-mapped. See Software access to the ETB11 using the AHB interface on

page 3-11.

This read/write register enables you to set and read the pointer used to write entries from

the ETM11RV into the RAM. Register bit allocations for the RAM Write Pointer

Note

is a constant used to define the width of the trace RAM address bus.

ETB_ADDR_WIDTH

You cannot write to this register if TraceCaptEn is HIGH.

The initial value of the trace memory write address pointer is set by writing to the RAM

Write Pointer Register. You must program the pointer before tracing starts. In most

circumstances the initial pointer value is zero. During trace capture, the pointer

increments when the DataValid flag is asserted by the Data Formatter. When the RAM

Write Pointer Register value increments from its maximum value back to zero, the Full

flag is set.

Reading the RAM Write Pointer Register returns the current trace RAM write address.

During trace capture, write pointer changes might be asynchronous. For example, if

DBGTCK is not related to the CPU clock, in this case the read back value is

indeterminate. This register only returns the correct write pointer value when trace

acquisition is stopped (when the AcqComp status bit is set or trace capture is disabled).

Table 3-8 RAM Write Pointer Register bit allocations

Bit number

[31: ETB_ADDR_WIDTH]

[(ETB_ADDR_WIDTH-1):0]

Function

Reserved

RAM write pointer

ARM DDI 0275D

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