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 ARM Cortex-M7 processor at 600MHz, with a NXP 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 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 ARM 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, 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. 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.
Tightly Coupled Memory is a special feature which allows Cortex-M7 fast single cycle access to memory using a pair of 64 bit wide buses. The ITCM bus provides a 64 bit path to fetch instructions. The DTCM bus is actually a pair of 32 bit paths, allowing M7 to perform up to two separate memory accesses in the same cycle. These extremely high speed buses are separate from M7's main AXI bus, which accesses other memory and peripherals. 512K of memory can be accessed as tightly coupled memory. Teensyduino automatically allocates your Arduino sketch code into ITCM and all non-malloc memory use to the fast DTCM, unless you add extra keywords to override the optimized default. Memory not accessed on the tightly coupled buses is optimized for DMA access by peripherals. Because the bulk of M7's memory access is done on the two tightly coupled buses, powerful DMA-based peripherals have excellent access to the non-TCM memory for highly efficient I/O.
Teensy 4.0's Cortex-M7 processor includes a floating point unit (FPU) which supports both 64 bit "double" and 32 bit "float". With M4's FPU on Teensy 3.5 & 3.6, and also Atmel SAMD51 chips, only 32 bit float is hardware accelerated. Any use of double, double functions like log(), sin(), cos() means slow software implemented math. Teensy 4.0 executes all of these with FPU hardware.
Note: Please be aware that the Teensy 4.0 does not include headers and will need to be purchased separately and soldered on yourself.
This skill defines how difficult the soldering is on a particular product. It might be a couple simple solder joints, or require special reflow tools.
Skill Level: Rookie - The number of pins increases, and you will have to determine polarity of components and some of the components might be a bit trickier or close together. You might need solder wick or flux.
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If a board needs code or communicates somehow, you're going to need to know how to program or interface with it. The programming skill is all about communication and code.
Skill Level: Competent - The toolchain for programming is a bit more complex and will examples may not be explicitly provided for you. You will be required to have a fundamental knowledge of programming and be required to provide your own code. You may need to modify existing libraries or code to work with your specific hardware. Sensor and hardware interfaces will be SPI or I2C.
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If it requires power, you need to know how much, what all the pins do, and how to hook it up. You may need to reference datasheets, schematics, and know the ins and outs of electronics.
Skill Level: Rookie - You may be required to know a bit more about the component, such as orientation, or how to hook it up, in addition to power requirements. You will need to understand polarized components.
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Based on 2 ratings:
Speed, versatility, ease of use and there is a wealth of support and information easily available.
After toying with dozens of different micro-controllers, large and small, the Teensy 4.0 came to my rescue. NXP brands the chip on the Teensy 4.0 as a crossover micro-controller which is quite accurate. The MXRT1062 has plenty of horsepower and resources to drive a real-time OS. You also get plenty of basic I/O needed for a modular designed project. All of that and it's still tiny, err, teensy.
My current project needs the following: A Lua interpreter, a real-time OS and some form of visual screen editor driven with PuTTY. The Teensy 4.0 handles all of this with room to spare. With a couple of headers I can attach the Teensy 4.0 to a larger circuit board and have it fully control all the hardware on that board. With a USB serial cable and an old laptop running PuTTY or minicom, I can field program the whole system in minutes using Lua as the onboard scripting language. The idea is to low-level program the Teensy once, then make field modifications without ever touching a Makefile or compiler ever again. The Teensy 4.0 fits this bill nicely.
You can get bigger, more powerful controllers able to run a full-blown Linux OS, but all that baggage comes at a price. The Teensy 4.0 is a right-sized controller in my opinion. It's something the market has overlooked for quite a while, but finally it's here. Give it a shot and see for yourself.
Oh and one other thing...
Speed isn't necessarily where it's all at. The Teensy 4.0 packs quite a bit of memory and flash on a single chip. I run my Teensy at 48MHz to keep it nice and cool while still performing a lot of work. But if you need to ramp this thing up for AI or Machine Learning, it can do that too, just have a decent heatsink handy, because it does get warm at higher clock speeds.