Posted on March 24, 2014 at 20:00Hi,
I cannot find this in the boot loader doc (AN2606) or on this forum. Do we need external pull-up or pull-down resistors on unused USART or CAN Rx signals? Or does the ROM-based boot loader (i.e. booting from system memory) enable the internal pull-up/down resistors while looking for activity on various USART/CAN/USB inputs? In my current design we want the USB boot loader to run and the USART/CAN Rx pins would otherwise be left as no-connects and I would really rather not have to put resistors there (severe space constraints).
Thanks.
#stm32-bootloader-pullups
