21.2.3 Compatibility

The 16-bit Timer/Counter has been updated and improved from previous versions of the 16-bit AVR Timer/Counter. This 16-bit Timer/Counter is fully compatible with the earlier version regarding:

• All 16-bit Timer/Counter related I/O Register address locations, including Timer Interrupt Registers.
• Bit locations inside all 16-bit Timer/Counter Registers, including Timer Interrupt Registers.
• Interrupt Vectors.

The following control bits have changed name, but have same functionality and register location:

• PWM10 is changed to WGM10.
• PWM11 is changed to WGM11.
• CTC1 is changed to WGM12.

The following bits are added to the 16-bit Timer/Counter Control Registers:

• FOC1A and FOC1B are added to TCCR1A.
• WGM13 is added to TCCR1B.

The 16-bit Timer/Counter has improvements that will affect the compatibility in some special cases.