Resolved! BRR register does not work for STM32L100RC and STM32L152RC boards
Posted on December 04, 2017 at 22:58RM0038 Reference manual states on page 188 that GPIOx_BRR register is available for Cat. 3 product - which includes both stm32l100rc and stm32l152rc (page 40 of Reference manual).But code below works when used BSR...