The STM32F103ZCT6: 112 I/O lines, 21-channel 12-bit ADC, and 2-channel 12-bit DAC.
Connectivity covers CANbus, USB, two I2C, three SPI, and five UART/USART with IrDA and LIN support. The 144-LQFP (20x20 mm) package gives access to all 112 GPIOs, which is the deciding factor when routing a dense backplane or a multi-axis drive with per-channel encoder and limit-switch inputs.
The STM32F103 series has broad second-source availability through the ST distribution network and independent channels, which supports dual-sourcing strategies for supply resilience.