6 Timer/Counter F (TCF)

TCF is a 24-bit timer optimized to act like a Numerically Controlled Oscillator (NCO). The NCO is a digital block consisting of an accumulator, an adder, and an increment. Every clock cycle, a set increment adds to the accumulated total. The remainder is added to the accumulator, and when the accumulator overflows, an output is generated. If the device is equipped with a PLL, the TCF can use it as a clock source.

Note: TCF runs asynchronously to the peripheral clock, which improves its flexibility. However, this leads to a delay when reading the timer count. Due to this, TCF is a better solution for frequency generation rather than precise timekeeping.

In PWM, the accumulator output is used to set the output. Then, a fixed (but user-settable) number of clock cycles later, the output clears. In fixed Duty Cycle mode, the accumulator output signal toggles an output flip-flop, generating a 50% duty cycle.