Release 1.9.12 - Serial and misc. fixes

• Fix hang on Serial overflow, PIOSerial stop bit handling (#401)
• Fix Nano_RP2040_Connect pinout issue (#400)
• Add the PIO UARTs to the list
• Add SDA/SCL variables like other cores export (#398)

Release 1.9.11 - PlatformIO and Adafruit QT Py fixes

• Fix A0-A3 pin definitions for Adafruit QT Py RP2040 (#397)
• Fix PlatformIO build (#395)

Release 1.9.10 - 10x faster SPI, better UART serial, PIO-based SoftwareSerial, Adafruit KB2040

• Add SoftwareSerial-like PIO based UARTs (#391)
• Use interrupts to capture Serial UART data, not polling (#393)
• Speed up SPI by not reinitting if the paramters are the same as before (#394)
• Add Adafruit KB2040 (#390)

Release 1.9.9 - SDK to 1.3.0, Serial1/2 fixes, precompiled libraries fixes

• Add warning not to edit boards.txt (#383)
• Remove redundant board.mcu in boards.txt, fix precompiled libs (#382)
• Add a poor-man's software FIFO for serial UART reads (#379)
• Update to SDK version 1.3.0 (#371)

Release 1.9.8 - More boards and CMSIS support

• Adds option for setting USB max power in makeboards.py (#370)
• Adds a lightweight support class for LTE functionality (#367)
• Adds support for Challenger NB RP2040 WiFi board and RPICO32 module (#366)
• Added new variant: Cytron Maker Nano RP2040. (#365)
• Support CMSIS and rename conflicting header file (#362)

Release 1.9.7 - Add WIZnet W5100S-EVB-Pico, update SDFat to 2.1.1

• Update pins_arduino.h for challenger_2040_wifi (#356)
• Add WIZnet W5100S-EVB-Pico board (#355)
• Update to SDFat 2.1.1 with UTF-8 support (#343)
• Add RTC headers to path and pico_utils to link (#353)

Release 1.9.6 - New boards and compilation options

• Correct typo in PlatformIO docs (#342)
• Add RTTI menu to support apps which need RTTI (#338)
• Add board variant for uPesy RP2040 DevKit (#335)
• Added board variants Cytron Maker Pi RP2040. (#340)
• Disable pull-up/pull-down when setting pin as input (#332)
• Fix Wire pin definitions on ItsyBitsy (#325)
• Add compiler Optimize option (#322)
• Change qtpy boot2 to w25q080_2_padded (#321)

Release 1.9.5 - Platform.IO, PulseIn fix, Adafruit board tweaks

• Build libpico.a with PICO_XOSC_STARTUP_DELAY_MULTIPLIER=64 (#315)
• Adds board variant definition for Melopero Shake RP2040 (#318)
• Add PlatformIO support (#250)
• Reset the SDA and SCL pins to INPUT at Wire.end() to prevent multiple pins connected to I2C when changing pins (#302)
• Fix pulseIn detection (#293)
• Fix wire defines on feather (#281)
• Added minimal HW support for onboard WiFi modem. (#287)
• Add support for reverse numbering of analog pins. (#283)

Release 1.9.4 - Bugfix for IRQ-related issues

• Don't use no-c++-exceptions version of libstdc++ (#280)
• Add support for our new Challenger RP2040 board with LTE modem. (#275)

Release 1.9.3 - PWM, Wire, Windows Python fixes, and new board

• Adds support for Challenger RP2040 WiFi boards (#268)
• Minor paranoid nullptr checks in USB interface (#267)
• Use Stream::setTimeout to specify I2C TO (#263)
• Make multiple SDFS/LittleFS.begin calls noops (#262)
• Fix JSON URL (#261)
• Set available() to 0 when Wire.requestFrom fails (#259)
• Added missing SPI::setCS(pin) in docs (#256)
• Fix upload file path escaping on Windows (#254)
• Avoid issues w/other installed Windows Pythons (#253)
• Remove exception handling code, save RAM and FLASH (#245)
• Fix PWM frequency at low and high frequencies (#244)