Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Keil/AT32F437xx_v2/USB_OTG2_HOST/HFNUM#0x0
OTGFS host frame number/frame time remaining register (OTGFS_HFNUM)
Frame number
Frame time remaining
https://github.com/cmsis-svd/cmsis-svd-data