In the STM32 timers, channels selected for Input Capture perform the capture upon edge of the input signal. In the vast majority of STM32 TIM, rising, falling or both-edges can be selected using CCxP and CCxNP bits in TIMx_CCER.

However, in the historically first STM32 family, the 'F1, timers don't have the both-edges option. Only TIMx_CCER.CCxP bit is used to select one of the rising/falling edge and there is no TIMx_CCER.CCxNP bit.

The so-called XL-density STM32F101xx and STM32F103xx microcontrollers with 768kB and 1MB FLASH (i.e. with xF or xG suffix) are a relative late coming addition to the 'F1 family. This is why in these, TIM9..TIM14, which were also an addition only in this sub-family and are not present in other 'F1, already do have the both-edge selection as other STM32 TIM do.