topic Re: LPC43XX I2C_CON_SI does not activate when used with ARM Compiler 6.21 in LPC Microcontrollers

LPC43XX I2C_CON_SI does not activate when used with ARM Compiler 6.21

lpestanas — Tue, 16 Sep 2025 01:56:22 GMT

Hi NXP Team,

I have encountered an issue about the LPC43XX I2C Transfer. In ARM Compiler 5.06, the Single byte write and all other I2C transactions works fine MCU to MCU. But upon selecting the ARM Compiler 6.21, the I2C_CON_SI bit is no longer firing resulting the slave device sending NACK to the I2C Master. The Optimization was disabled and volatiles were placed along the memory-mapped I2C Peripheral declaration. Does anyone encounter this using ARM Compiler 6?

Thanks and Good Day,

Leo

Re: LPC43XX I2C_CON_SI does not activate when used with ARM Compiler 6.21

Harry_Zhang — Thu, 18 Sep 2025 09:52:40 GMT

Hi @lpestanas

Can we reproduce this issue?

Harry

Re: LPC43XX I2C_CON_SI does not activate when used with ARM Compiler 6.21

lpestanas — Mon, 22 Sep 2025 00:57:09 GMT

Hi Harry,

This was solved by putting "volatile" keyword on the structure declaration that post-processes the data from I2C Driver Registers. This problem can be examined between ARM Compiler 5.06 and ARM Compiler 6.21 using LPC4330FBD144 as our MCU. We mark this issue closed as of now.

Thanks and Good Day,
Leo