nRF52832: MPU FAULT (Instruction Access Violation in RAM) when using custom bare-metal TWIM0 ISR in Zephyr

RE: nRF52832: MPU FAULT (Instruction Access Violation in RAM) when using custom bare-metal TWIM0 ISR in Zephyr

jswcomkr — Thu, 26 Feb 2026 06:23:34 GMT

Thank you. I finally resolved the error.
This problem was caused by a duplicated callback function name in the same project.
I had added an old custom library for TWIM, and it had the same callback function, 'TWIM0_IRQHandler', too. So, I removed it from CMakeLists.txt and everything is working well.

Reviewing the map file is very useful tool for this case.

RE: nRF52832: MPU FAULT (Instruction Access Violation in RAM) when using custom bare-metal TWIM0 ISR in Zephyr

Vidar Berg — Thu, 26 Feb 2026 06:06:24 GMT

Hello,

I tried running your code but did not manage to reproduce the crash. Attached below is the project I used.

devzone.nordicsemi.com/.../3582.hello_5F00_world_5F00_i2c.zip

[quote user=""]RAM address (e.g., 0x200010d0), which is located immediately after my RX/TX static arrays (rxd, txd).[/quote]

Please check with variable or region this address belong to in your zephyr.map.

Best regards,

Vidar

RE: nRF52832: MPU FAULT (Instruction Access Violation in RAM) when using custom bare-metal TWIM0 ISR in Zephyr

jswcomkr — Thu, 26 Feb 2026 04:29:21 GMT

Hello,

I already tried that, even after removing the rxd and txd variables.

RE: nRF52832: MPU FAULT (Instruction Access Violation in RAM) when using custom bare-metal TWIM0 ISR in Zephyr

Vidar Berg — Wed, 25 Feb 2026 18:07:20 GMT

Hello,

Please try removing the "static" keyword from your function prototype so that it matches the function definition for your ISR. The problem is that your interrupt vector is not pointing to TWIM0_IRQHandler() function.

Best regards,

Vidar