New Feature Highlights

• Added board headers for Adafruit, Pimoroni & SparkFun boards

  • new values for PICO_BOARD are adafruit_feather_rp2040, adafruit_itsybitsy_rp2040, adafruit_qtpy_rp2040, pimoroni_keybow2040, pimoroni_picosystem, pimoroni_tiny2040, sparkfun_micromod, sparkfun_promicro, sparkfun_thingplus, in addition to the existing pico and vgaboard.
  • Added additional definitions for a default SPI, I2C pins as well as the existing ones for UART
  • Allow default pins to be undefined (not all boards have UART for example), and SDK will compile but warn as needed in the absence of default.
  • Added additional definition for a default WS2812 compatible pin (currently unused).

• New reset options

  • Added pico_bootsel_via_double_reset library to allow reset to BOOTSEL mode via double press of a RESET button
  • When using pico_stdio_usb i.e. stdio connected via USB CDC to host, setting baud rate to 1200 (by default) can optionally be used to reset into BOOTSEL mode.
  • When using pico-stdio_usb i.e. stdio connected via USB CDC to host, an additional interface may be added to give picotool control over resetting the device.

• Build improvement for non SDK or existing library builds

  • Removed additional compiler warnings (note register headers now use _u(x) macro for unsigned values though).
  • Made build more clang friendly.

This release also contains many bug fixes, documentation updates and minor improvements.

Note: there are some nominally backwards incompatible changes not worthy of a major version bump: - PICO_DEFAULT_UART_ defines now default to undefined if there is no default rather than -1 previously - The broken multicore_sleep_core1() API has been removed; multicore_reset_core1 is already available to put core 1 into a deep sleep.