3.2 Harmonic Analysis

Harmonic analysis control-related registers are allocated in FEATURE_CTRL1.

HARMONIC_m_REQ must be set first, the valid HARMONIC_m_REQ value range is 1 to 21 but may be higher depending on system frequency limitations.

When HARMONIC_m_REQ is set to m, the m-th harmonic will be analyzed once enabled by setting HARMONIC_EN to 1. After harmonic analysis is enabled, the analysis request is latched and begins at the start of the next integration period with results available at the end of that integration period.

Because a different harmonic analysis can be made every integration period, a specific harmonic analysis may be requested and latched at the start of an integration period, then HARMONIC_m_REQ may be changed to a different harmonic to be latched processed at the start of the following integration period. This way, a different harmonic may be analyzed each and every integration period.

At the end of each harmonic analysis, HARMONIC_m_CONF is updated with the number of the harmonic just processed. When HARMONIC_m_CONF is equal to the HARMONIC_m_REQ requested at the start of the previous integration period, the desired harmonic results will be present in the harmonic accumulators.

Note: When enabled, the harmonic analysis result is updated every integration period. INTEGRATION_IRQ will be generated at the end of the integration period; this interrupt can be used to update the harmonic analysis result.