Main features: - 74 GPIO pins across multiple headers. - A specialised 16 x 2 header marked "TFT" (16 data pins + strobes, plus SPI for touch). - A 2 x 10 JTAG/DBG IDE header. - An 8 pin female header for NRF24L01 RF (not WiFi) module. - Mini SD slot. - Mini USB which provides USB Serial (VCP) via the ST VCP driver (Read ALL the instructions when installing the driver - it's a 2-step process.) - 4 buttons (RST, K..UP, K0, K1) - Three LEDs: "D1" = Power LED; "D2" = PA6 & "D3" = PA7 - RTC and 8MHz crystals. RTC backup battery (CR 1220) - -Many boards are fitted with additional flash - often a Winbond W25Q16 chip (16M-bit, 4KB erasable sectors & 32KB/64KB erasable blocks). Flash memory is on SPI1 - shared SPI with nRF2401 header (different /CS pins).