Polyphase metrology MCU with six simultaneous sigma-delta channels
The MSP430F67671AIPZR: Rated for the industrial temperature range of -40 to 85°C and supplied at 1.8 V to 3.6 V, it fits outdoor cabinet, substation, and factory-floor environments where the analog front end must stay accurate across thermal swings.
Six 24-bit sigma-delta ADCs — what simultaneous sampling means for the BOM
The six 24-bit sigma-delta converters are the part's headline differentiator. Each ADC pair (one voltage, one current per phase) samples simultaneously, so the phase angle between voltage and current is captured in the same instant — no external sample-and-hold or multi-chip synchronisation needed. For a three-phase meter, this eliminates the per-phase ADC and the isolation amplifier that a discrete front end would require, collapsing the analog BOM to a resistor divider and a current-sense transformer per phase. The 32 KB of RAM is the practical ceiling for buffering polyphase metrology data and LCD frame storage. With six channels streaming 24-bit samples, the firmware engineer needs to budget the sample buffer size against the available RAM — 8 KB per channel would exceed the total, so the metrology loop must process and decimate in real time rather than batch-store raw samples.
On-chip peripherals — LCD driver, DMA, brown-out detect
Beyond the ADC bank, the peripheral set includes a brown-out detect and reset, DMA controller, LCD driver, POR, PWM timer, and watchdog timer. The DMA can move ADC conversion results directly to RAM without CPU intervention — useful when the metrology loop must keep the sigma-delta channels fed while the CPU handles communication stacks or display updates. The internal oscillator eliminates an external crystal for the main clock, though the UART and CAN timing may still benefit from an external resonator if tight baud-rate tolerance is required.