Tag Archives: cortex-m7

Introduction to the ARM® Cortex®-M7 Cache – Part 3 Optimising software to use cache

Director at Feabhas Limited
Co-Founder and Director of Feabhas since 1995.
Niall has been designing and programming embedded systems for over 30 years. He has worked in different sectors, including aerospace, telecomms, government and banking.
His current interest lie in IoT Security and Agile for Embedded Systems.

Caches – Why do we miss?
Cold Start

As stated, both data and instruction caches are required to be invalidated on system start. Therefore, the first load of any object (code or data) cannot be in cache (thus the cold start condition).

One available technique to help with cold-start conditions is the ability to pre-load data into the cache. The ARMv7-M instruction set adds the Preload Data (PLD) instruction. The PLD instruction signals to the memory system that data memory accesses from a […]

Posted in ARM, C/C++ Programming, CMSIS, Cortex, Design Issues | Tagged , | 1 Comment

Introduction to the ARM® Cortex®-M7 Cache – Part 1 Cache Basics

Director at Feabhas Limited
Co-Founder and Director of Feabhas since 1995.
Niall has been designing and programming embedded systems for over 30 years. He has worked in different sectors, including aerospace, telecomms, government and banking.
His current interest lie in IoT Security and Agile for Embedded Systems.

For many years, the majority of smaller microprocessor-based systems have typically not used caches. With the launch of the ARMv7 architectures, caches were supported in the ARMv7-A family (e.g. Cortex-A8, etc.) but not supported in the core design of the ARMv7-M micro-controllers such as the Cortex-M3 and Cortex-M4. However, when the Cortex-M7 was announced, it broke that mould by offering cache support for the smaller embedded micro-controller.

This series is broken down in three parts:

Basic principles of cache
Cache replacement policies
Optimising software […]

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