90 MHz C28x core — real-time control loop headroom
The TMS320F28066PZT is a 32-bit C2000 C28x Piccolo MCU from Texas Instruments, built around a single-core C28x DSP running at 90 MHz. This clock rate determines how fast the control loop can execute — for a typical 10 kHz PWM switching frequency, the core has roughly 9000 instruction cycles per interrupt to run the current regulator, flux estimator, and communication stack before the next cycle starts. The 256 KB on-chip Flash (128K x 16) and 34K x 16 RAM provide enough space for field-oriented motor control or digital power conversion firmware with CAN and UART stacks.
Analog interface — 16-channel 12-bit ADC
The part integrates a 16-channel, 12-bit ADC — enough to sample three-phase currents, DC-link voltage, and a few auxiliary analog inputs in a motor drive without external multiplexing. The 12-bit resolution is adequate for 0.1% current sensing with a suitable shunt and amplifier; if higher precision is needed, an external 16-bit ADC would be required. The ADC is sequenced by the PWM module, so samples can be triggered synchronously with the switching edges.
The 54 general-purpose I/O pins are enough to interface with external sensors, relays, and an encoder interface without an I/O expander. Internal oscillator is available, though an external crystal is recommended for precision PWM timing.
For production BOMs, the active status removes the urgency of a lifetime buy, though the usual PCN monitoring for package or wafer-fab changes still applies.