Hello all,
I would like to add few thoughts to this interesting thread:
not so many are aware of the application differences between a realtime hardware and a Linux OS board with a scheduler, my job is electronic engineer, independent contractor and almost all my new customers, they usually come with the request to implement every kind of products you can imagine with the Raspberry PI and Linux, even for robots, controllers, UAV, all applications typical of the realtime world. This attitude is largely influenced by hackers/makers community, which I support of course, but not beyond the scope of exploration, testing ideas and laboratory to earn knowledge, industrial products requires appropriate design.
Even if exists a Linux kernel version with a pseudo realtime scheduler, its proper applications are still limited to video/medias processing, VOIP, audio processing, applications typical of a shared OS environment as desktop or industrial appliances. Deep learning or OpenCV are software applications for an high level OS for instance.
Realtime MCUs are designed for other kind of applications where deterministic interruptions are crucial, GPIO events or timed functions needs to get executed at precise moments, examples are self balancing robots or UAV controllers such as the Pixhawk. Recently BleagleBone came out with a Blue version specific for robotics, the Linux OS is running on the ARM cortex-A8 core but all the realtime stuff get executed inside 2 integrated PRU 32-bit realtime microcontrollers specific for those kind of applications, there is no way to achieve the execution of realtime tasks inside an OS running on a Raspberry PI for instance.
So different applications require different hardware architectures.
The Teensy 4.0 aims to improve and expand the design possibilities in the realtime world, maybe with a realtime OS such as NUTTX or FREERTOS, there are many more..
These days I am designing a device with RTK+PPK GPS capabilities based on Teensy 3.6, it needs to have a maximum acceptable latency in order of the ms, added with other heavy processing of the readings from sensors.
The future Teensy 4.0 will be useful in my case, because one day I need to add an integrated crypto hardware accelerator in order to support encrypted datastream in realtime and at the same time, to integrate all the features of an UAV controller.
I feel we are just at the beginning with these high performances realtime MCUs, there are plenty of real world applications for the next Teensy 4.0, applications that finally can be implemented with just a single MCU, so I am happy to hear about this new version.
Best luck Paul!