If you are trying to make sense of high-speed Timer 4 on Microchip’s (Atmel’s) ATmega 32U4, someone called dmm47 has put a useful little resource onto the Arduino forum. At the very minimum, it saves you typing in all the register names, and saves you missing out a register. This is not a universal resource, but …
This story continues at Useful little resource for high-speed Timer 4 on the ATmega32U4
Or just read more coverage at Electronics Weekly