Frequency (FRQ) Waveform Generation

For frequency generation, the period time (T) is controlled by a TCA.CMPn register instead of the Period register (TCA.PER). The waveform generation output WG is toggled on each compare match between the TCA.CNT and TCA.CMPn registers.

Figure 1. Frequency Waveform Generation

The waveform frequency (fFRQ) is defined by the following equation:


where N represents the prescaler divider used (CLKSEL in TCA.CTRLA), and fCLK_PER is the system clock for the peripherals.

The maximum frequency of the waveform generated is half of the peripheral clock frequency (fCLK_PER/2) when TCA.CMPn is written to zero (0x0000) and no prescaling is used (N=1, CLKSEL=0x0 in TCA.CTRLA).