Teensy 4.0 is the latest Teensy, offering the fastest microcontroller and powerful peripherals in the Teensy 1.4 by 0.7 inch form factor. It features an Cortex-M7 processor at 600MHz, with a iMXRT1062 chip, the fastest microcontroller available today. Teensy 4.0 is the same size and shape as Teensy 3.2, and retains compatibility with most of the pin functions on Teensy 3.2. When running at 600 MHz, Teensy 4.0 consumes approximately 100mA current. Teensy 4.0 provides support for dynamic clock scaling. Unlike traditional microcontrollers, where changing the clock speed causes wrong baud rates and other issues, Teensy 4.0 hardware and Teensyduino's software support for Arduino timing functions are designed to allow dynamically speed changes. Serial baud rates, audio streaming sample rates, and for Arduino functions like delay() and millis(), and Teensyduino's extensions like IntervalTimer and elapsedMillis, continue to work properly while the CPU changes speed. Teensy 4.0 also provides a power shut off feature. By connecting a pushbutton to the On/Off pin, the 3.3V power supply can be completely disabled by holding the button for 5 seconds, and turned back on by a brief button press. If a coin cell is connected to VBAT, Teensy 4.0's RTC also continues to keep track of date & time while the power is off. Teensy 4.0 also can also be overclocked, well beyond 600MHz! The Cortex-M7 brings many powerful CPU features to a true real-time microcontroller platform. Cortex-M7 is a dual-issue superscaler processor, meaning the M7 can execute two instructions per clock cycle,600MHz!executing two simultaneously depends upon the compiler ordering instructions and registers. Initial benchmarks have shown C++ code compiled by Arduino tends to achieve two instructions about 40% to 50% of the time while performing numerically intensive work using integers and pointers. Tightly Coupled Memory is a special feature which allows Cortex-M7 fast single cycle access to memory using a pair of