The Serial Peripheral Interface (SPI) is used to communicate between the DSP and the AVR MCU in the PMU, and it allows PMU to operate independently to measure, record, and display and transfer both the instantaneous and phase data.

• PMU内部DSP与AVR单片机之间采用串行外围接口(SPI)实现高速可靠通信,以便AVR单片机完成瞬时数据和相量数据的记录、显示和通信,实现PMU独立运行;