The manual of ETM tells that the ETM supports data trace. However, we checked the manual of Juno board and most recent Cortex A75 processors, and found that the data trace is not implemented. Currently, is there any ETM supporting data trace in the market?
Thanks for any help and discussion!
I assume you need ETMv4? Cortex-M7 should be widely available and implements ETMv4.0. You'll find data trace in processors that are less complex, which rules out ever seeing it on a Cortex-A processor, although I believe some of the older or more efficient Cortex-A8, Cortex-A5 may have data address (but not data value) trace on older ETM architectures.
Hi Matt,
Would you mind I ask one more question? I am litter curious about the design of data trace. Why the most recent and powerful ARM processors do not support the data trace, but the old processors and MCUs support this feature?
Best,
Zhenyu
Simply put, it adds overhead (and complicated timing paths!). Newer and faster processors are more complex designs and it becomes more difficult to keep track of the same amount of information while at the same time assuring that it can be transmitted as trace.
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