The /202 variant omits the crystal oscillator option and relies on its internal oscillator, saving one external component.
Programming and debug use the standard Serial Wire Debug (SWD) interface — two pins (SWDIO and SWCLK) plus Vcc and GND. Any ARM-compatible debug probe (J-Link, ST-Link, CMSIS-DAP) works. No external crystal is required for SWD because the internal oscillator provides the debug clock.
