Value-line Cortex-M3 for cost-sensitive control
The STM32F100CBT6B: This part targets cost-sensitive embedded control applications — motor drives, sensor interfaces, and human-machine interfaces — where the 24 MHz core and integrated peripherals (DMA, PWM, 10-channel 12-bit ADC, dual 12-bit DAC) cover the control loop without the overhead of a higher-performance sibling.
At 24 MHz, the Cortex-M3 executes most single-cycle instructions, giving roughly 24 MIPS. That is enough for a 10 kHz current-control loop with headroom for communications overhead.
Memory sizing: 128 KB Flash, 8 KB RAM
128 KB of Flash is sized for moderate firmware — a bootloader, a real-time kernel, and application code for a motor drive or a simple HMI. The 8 KB SRAM is tight for data buffers.
On-chip peripherals include DMA, a power-on reset (POR), a programmable voltage detector (PVD), a temperature sensor, and a watchdog timer. The 37 general-purpose I/Os are multiplexed with these peripherals, so check the alternate-function mapping in the datasheet when planning your pin allocation.