If you're working with an STMicroelectronics MCU, you'll need a timing device. ECS Inc. International has been featured in over 60 references for the STM32 LSE kHz clocks and 600 references for the HSE MHz clock. ECS Inc.'s crystal selection tool aids in selecting the appropriate crystal for your design. ECS Inc. STM32 Reference Designs: https://ecsxtal.com/stmicro-stm32-reference-designs-32768khz/ ECS Inc. Crystal Selection Tool: https://ecsxtal.com/news-resources/stm32-crystal-selection-tools/ ECS Inc. International 15351 W. 109th Street Lenexa, KS 66219 (913) 782-7787 www.ecsxtal.com engineering@ecsxtal.com