This is a collection of misc libraries, examples, etc. for stm32f103 (aka blue pill) + libopencm3
(+ FreeRTOS, sometimes)

AD9850
========

Control some DDS like AD9850 and AD9851.

This library doesn't use SPI, just regular GPIO: this is simpler (imho) to implement and understand, and gives
you freedom to use whichever pin you prefer.

Notes
-------
Support for ad9833 is completely lacking (despite some code you might find).

I am uncertain about ad9850/1: the two are similar, and I have some difficulties understanding which do I
have. However, I think the implementation is correct.

Rotary TBL
===========

Rotary encoder reading implemented with interrupts and lookup tables. This implementation uses a single
interrupt, both on rising and falling.

Credits to http://makeatronics.blogspot.com/2013/02/efficiently-reading-quadrature-with.html

_This is not a library, just an example_

The example uses FreeRTOS just for convenience, you can easily remove it.

Rotary TBL2
===========

Same as before, but with interrupts on both ports of the rotary encoder. It is more precise but, well, "uses"
one more interrupt.

Credits to http://makeatronics.blogspot.com/2013/02/efficiently-reading-quadrature-with.html

The example uses FreeRTOS just for convenience, you can easily remove it.

_This is not a library, just an example_

SSD1306
=======

Controls the oled display SSD1306.

SPI is used, so you don't have complete freedom on which pin/port to choose.