The question pertains to maximum rise time specification for STM32L151CC OSC32_IN when Low-speed external user clock is generated from an external source.

The question pertains to maximum rise time specification for STM32L151CC OSC32_IN when Low-speed external user clock is generated from an external source. This specification, according to the datasheet, is 10 nano seconds. This seems unreasonably fast, unless the input does not have schmitt trigger. If the lack of schmitt trigger is the reason for this requirement, is there a way to enable schmitt trigger for the PC14 pin, when it is used to receive an LSE external clock source?