9.15.2. RAM options

RAM width is 32 bits. This minimizes buffering in the formatter and ensures that the Trace RAM can be used as slow software-accessible memory.

The RAM depth is configurable by setting the address bus width using CSETB_RAM_ADRW, as shown in Table 9.23. Previous implementations of the ETB did not specify a lower and upper range of RAM configurations. ARM currently recommends customers adopt a minimum RAM size of 4KB. The range specified covers both ends of requirements, and meets future trace storage requirements.

Table 9.23. ETB RAM size options

Address rangeWords storedTotal storage in KB
[7:0]256 1
[8:0]512 2
[9:0]1 024 4
[10:0]2 048 8
[11:0]40 96 16
[12:0]8 192 32
[13:0]16 384 64
[14:0]32 768 128
[15:0]65 536256
[16:0]131 072512
[17:0]262 1441 024

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