better readme

README.md

@@ -1,2 +1,48 @@
 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.

ad9850/README.md

@@ -1,12 +0,0 @@
-AD98xx
---------
-
-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.