72 MHz Cortex-M3 with 384 KB Flash — the high-density workhorse
The 144-LQFP package exposes 112 I/O, the highest pin count in the STM32F103 line, making it the natural choice when you need a parallel LCD interface, an external memory bus, or a large number of GPIOs for a control panel or industrial I/O module.
If the end system sees sustained ambient above 85°C, check whether the extended-temperature variant (STM32F103ZDT6 with a '7' suffix) is available; this listing is the standard industrial grade.
Analog and connectivity peripherals
Connectivity includes CANbus, I²C, SPI, UART/USART, USB, and IrDA, so it can serve as the central node in a distributed control network or a gateway between a CAN fieldbus and a USB host.
Supply voltage and power management
Built-in peripherals include a power-on reset (POR), power-down reset (PDR), and programmable voltage detector (PVD), which simplify the power sequencing and brown-out handling on a multi-rail board.
Active lifecycle — no obsolescence signal
The STM32F1 series is a mature, volume-production line with no last-time-buy notices or end-of-life announcements for this density. That makes it a safe choice for production programs with a multi-year horizon, though the usual allocation watch applies during tight market cycles — the STM32F1 has seen spot premiums in past shortages.