Arm Mbed OS support forum

STM32F767ZI LSE Crystal Crashes


I am using a custom board with the STM32F767ZI and am having issues with a crash that results in the error HAL_RCC_OscConfig ERROR. The board was working fine until I washed it with alcohol and a toothbrush as there was some flux residue that was on the board, and now it will rarely work. If in mbed_app.json I define “target.lse_available”: 0, it will work, meaning that the LSE is the issue. Are these MCUs particularly sensitive to how the crystal is set up? I am using the correct value crystal with 2pF capacitors.