Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32f2/STM32F215/OTG_HS_HOST/OTG_HS_HFNUM#0x0
OTG_HS host frame number/frame time remaining register
Frame number
Frame time remaining
https://github.com/modm-io/cmsis-svd-stm32