The SPI bus is shared between all four ADCs and the MCU features an SPI controller with four separate Chip Select (CS) lines, one of each connecting to an ADC. The SPI bus runs at a 19.968MHz or 13,312MHz data rate with DMA support using two channels, one for transmit and one for receive. The PICO and POCI data lines are shared, as these are driven sequentially with only one CS line active at a time.

The four DRDY lines (one from each ADC) are wired to four GPIO inputs with interrupt enabled on the falling edge.

Three GPIO outputs are needed:

1. One SYNC_RESET line to trigger all ADCs simultaneously, SYNC_RESET is shared by all ADCs
2. ACT output
3. REACT output

The ACT and REACT pulsed outputs are used to report the Active and Reactive energy being calculated by the metrology middleware. The ACT and REACT outputs and are used to measure the TIDA-010244 accuracy using an external test system, which reads these ACT and REACT pulses.

An I2C interface is used to connect the TMAG5273 3D Hall-sensor device, with the MCU being the I2C transmitter. The RTC module supports calendar mode, which is a common requirement for an electricity meter. The M0+ MCU internal 32.768kHz LFOSC is used as the clock source for the auxiliary clock (RTCCLK) of the device.