Memory and throughput for closed-loop control
The 70 MIPs execution rate is the key spec for a control-loop designer: at 70 million instructions per second, a 10 kHz current-control loop has 7000 instruction cycles per iteration, enough for a PID with feedforward and a sensor filter. The 128 KB Flash (43K x 24) holds the firmware and a lookup table for motor profiles or sensor linearisation, while the 8K x 16 SRAM buffers ADC samples and state variables without spilling to external memory. The six-channel 10-bit/12-bit ADC (A/D 6x10b/12b) samples synchronously with the PWM timers, so the controller reads phase currents at the switching edge without software jitter. The DMA peripheral moves ADC results directly to RAM without CPU intervention, preserving MIPs for the control algorithm.
28-SPDIP: through-hole fit and board assembly
The 28-pin SPDIP (0.300-inch row spacing, 7.62 mm body width) is a through-hole package that suits hand-assembly, rework, or low-volume wave-solder production. The 21 general-purpose I/O lines are enough for a sensor interface with a few discrete outputs; the remaining pins are dedicated to the oscillator, supply, and programming/debugging (ICSP). The 3V to 3.6V supply rail is common to 3.3V systems; a single 3.3V regulator with a 100 nF decoupling cap per supply pin is the standard bypass recommendation.