https://devzone.nordicsemi.com/f/nordic-q-a/7821/when-to-use-the-cmsis-apisI am new to programming both the nRF518122 as well as the Cortex-m0. As I have been building and running the example apps that come with the nrf51 sdk, I run across the CMSIS APIs I have recently started using the Eclipse IDE for nRF51 DK developmenten-USTelligent Community 13Thu, 25 Jun 2015 11:28:56 GMThttps://devzone.nordicsemi.com/thread/27859?ContentTypeID=1Thu, 25 Jun 2015 11:28:56 GMT137ad170-7792-4731-bb38-c0d22fbe4515:eff0874c-ff46-4988-88d9-219d9eee13c7i_am_trying<p>Thank you. Your answer helped clarify. I upvoted.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/27858?ContentTypeID=1Thu, 25 Jun 2015 02:04:05 GMT137ad170-7792-4731-bb38-c0d22fbe4515:2521d3c4-e8b6-4bee-869f-2e8f69f77dcfNguyen Hoan Hoang<p>At a minimum CMSIS API contains the initialization of the processor. The nRF51 SDK also uses it and all other ARM based MCU. The minimum implementation is the file system_nrf51.c. It contains SystemInit and SystemCoreClock. Beside from the init functions which are usually provided by the chip vendor. CMSIS also contains many utility functions and DSP mathematical implementation that are optimized for ARM. If you work in multi vendor environment, it is better to have the CMSIS in one place to be use by all.</p><div style="clear:both;"></div>