Re: Teensy 3.5/3.6 upgrade for uBITX

Jerry Gaffke

I'd bet worst case latency on a not seriously loaded RPi is less than the
milliseconds it takes us to load a new clock frequency into the si5351 via 100khz i2c.

A google for "Rasberry Pi RT" shows there are real time variants of the kernel.
I've got no idea how real time. 

There are some going without linux, programming the bare metal.

But I like the idea of still using a simple microntroller for basic rig control.
Being something of a pessimist, I'd prefer not to depend on something
as complex as the RPi, too many billions of things that could go wrong.


On Mon, Apr 23, 2018 at 11:01 am, Robert Weiman wrote:
The one big difference in this application between the Raspberry Pi and a micro-controller like the Teensy and the Arduinos is how much overhead the OS imposes.  Linux is a full blown consumer OS and is not a real-time OS.  It can impose non-deterministic delays on how long it takes to respond to an interrupt / toggle an I/O pin / etc.  On most of the hobby micro-controllers, there is significantly less overhead imposed by minimal, almost not really an OS, provided by the Arduino build environment.  Personally, I will add a PI to my uBitx build, but it won't be replacing the micro-controller in the Raduino - more augmenting the system by providing higher level software and interfaces (Digital modes, etc).  

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