https://test-devzone.nordicsemi.com/f/nordic-q-a/88425/prevention-of-running-code-from-ramHi. Can the nrf52840 prevent running code from RAM ? in general ? I know there are bits of code in the nrf sdk that transform byte codes into a function (so it&#39;s in ram) and then run it, but i want to prevent like in modern OSes running from the stacken-USTelligent Community 13 Non-ProductionTue, 31 May 2022 07:06:09 GMThttps://test-devzone.nordicsemi.com/thread/370103?ContentTypeID=1Tue, 31 May 2022 07:06:09 GMT137ad170-7792-4731-bb38-c0d22fbe4515:2de109a3-6af5-4057-b07f-334bdddf86eduser7377<p>Hi,</p> <p>The <a href="https://developer.arm.com/documentation/ddi0439/b/Memory-Protection-Unit/About-the-MPU">MPU</a> can be used to prevent code execution from RAM. If you use the nRF Connect SDK, which is Zephyr based, this is&nbsp;prevented by default. See <a href="https://docs.zephyrproject.org/latest/hardware/arch/arm_cortex_m.html#memory-map-and-mpu-considerations">Memory map and MPU considerations</a>, specifically:</p> <p style="padding-left:30px;"><em>One MPU region programs the entire SRAM area with privileged-only RW permissions. That is, an MPU region is utilized to disallow execute permissions on SRAM.</em></p> <p>If you are using the nRF5 SDK you have to enable this yourself, for instance using the <a href="https://infocenter.nordicsemi.com/topic/sdk_nrf5_v17.1.0/lib_mpu.html">MPU driver</a>.</p><div style="clear:both;"></div>