by Joseph Yiu
The Arm Cortex-M family now has five processors. In this paper, we compare the features of various Cortex-M processors and highlight considerations for selecting the correct processor for your application. The paper includes detailed comparisons of the Cortex-M instruction sets and advanced interrupt capabilities, along with system-level features, debug and trace features, and performance comparisons.
Since writing this block we have announced further additions to the Cortex family, Cortex-M23 and Cortex-M33, and updated the document. The latest version is available here: Cortex-M for Beginners - An overview of the Arm Cortex-M processor family and comparison (2017).
Arm Cortex-M23 and Cortex-M33 are the first embedded processors using the Armv8-M architecture, bringing the proven secure foundation of Arm TrustZone to the most constrained IoT nodes.
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I was considering that the IRQ number and the exception would be the same, is that the diagram of Figure 8 gives understand, and did not consider that the exception count starts when it comes to user IRQs, starting the exception 16, so should not the column "Exception Type" count to 254? For Armv6-M is correct (31), but for the Armv7-M is outdated. Ie 240 user IRQs and 16 exceptions system.