48 MHz Cortex-M0 with USB and CAN in a 20-pin TSSOP
It packs a USB 2.0 full-speed device controller and a CAN 2.0B interface into a 20-pin TSSOP package, which is unusual for this pin count — most 20-pin MCUs in this class omit CAN or USB.
Peripheral set and memory sizing for the BOM
The 6 KB SRAM handles a couple of 1 KB DMA buffers plus stack and global data; if your application needs a large frame buffer or a TCP/IP stack, step up to the 8 KB or 16 KB SRAM variants in the STM32F042 family.
STMicroelectronics continues to manufacture the STM32F0 series, and the base product number STM32F042 spans multiple density and package options that share the same peripheral set, easing a future density migration without a board respin.