STMicroelectronics STM32F05 series Reference Manual page 347

RM0091 General-purpose timers (TIM2 and TIM3)
Bits 31:16 CCR2[31:16]: High Capture/Compare 2 value (on TIM2).
Bits 15:0 CCR2[15:0]: Low Capture/Compare 2 value
If channel CC2 is configured as output:
CCR2 is the value to be loaded in the actual capture/compare 2 register (preload value).
It is loaded permanently if the preload feature is not selected in the TIMx_CCMR2 register
(bit OC2PE). Else the preload value is copied in the active capture/compare 2 register when
an update event occurs.
The active capture/compare register contains the value to be compared to the counter
TIMx_CNT and signalled on OC2 output.
If channel CC2 is configured as input:
CCR2 is the counter value transferred by the last input capture 2 event (IC2).
Doc ID 018940 Rev 1 347/742