he Teensy 4.1 is the newest iteration of the astoundingly popular development platform that features an ARM Cortex-M7 processor at 600MHz, with a NXP iMXRT1062 chip, four times larger flash memory than the 4.0, and two new locations to optionally add more memory. The Teensy 4.1 is the same size and shape as the Teensy 3.6 (2.4in by 0.7in), and provides greater I/O capability, including an ethernet PHY, SD card socket, and USB host port. The best part of this version of Teensy 4.1 is that it includes headers already attached. No soldering is required allowing you to get started as quickly as possible!
When running at 600 MHz, the Teensy 4.1 consumes approximately 100mA current and provides support for dynamic clock scaling. Unlike traditional microcontrollers, where changing the clock speed causes wrong baud rates and other issues, Teensy 4.1 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 Arduino functions like delay() and millis(), and Teensyduino's extensions like IntervalTimer and elapsedMillis, continue to work properly while the CPU changes speed. Teensy 4.1 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 five seconds, and turned back on by a brief button press. If a coin cell is connected to VBAT, Teensy 4.1's RTC also continues to keep track of date & time while the power is off. Teensy 4.1 also can also be overclocked, well beyond 600MHz!
The ARM Cortex-M7 brings many powerful CPU features to a true real-time microcontroller platform. The Cortex-M7 is a dual-issue superscaler processor, meaning the M7 can execute two instructions per clock cycle, at 600MHz! Of course, 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. The Cortex-M7 is the first ARM microcontroller to use branch prediction. On M4, loops and other code which much branch take three clock cycles. With M7, after a loop has executed a few times, the branch prediction removes that overhead, allowing the branch instruction to run in only a single clock cycle.
