Update docs and clear unused avr files

Author: ckormanyos

examples/chapter09_08b/readme.md

@@ -1,107 +1,18 @@
-# Example Chapter09_08a
+# Example Chapter09_08b (variation 32-bit microcontroller)
 ## Controlling an RGB LED of type ws2812
 
-Example chapter09_08a utilizes object oriented programming techniques
-to control an industry-standard RGB LED of type ws2812
-
-This example controls an RGB LED using programming techniques similar to those used in the previous example.
-There are, however, several differences such as the refactored, modernized LED-class hierarchy.
-The main difference, however, is that a _digitally_-controlled industry-standard
-RGB LED of type ws2812 is used. In addition, the color transitions at (and around) $255~\text{bits}$-RGB
-are slowed down providing emphasized, longer-lasting RGB hues near these points.
-
-## Controlling the ws2812
-
-The ws2812 RGB LED is controlled by a very specifically timed,
-novel digital signal. In this signal, each of the $24$ RGB
-color bits is set to the value $1$ or $0$ depending on the
-half-width of a low/high signal pair.
-
-In this example (as in most other examples), both a hardware
-version for the target system as well as a simlulated PC
-version are available. For this exercise, it was
-decided to implement a rather detailed PC simulation
-using old-school traditional Win32-API programming.
-
-## Application Description
-
-Strikingly bright, vibrant hues of RGB blend in a smooth fashion around the entire
-spectrum to produce the appearance of evenly varying colors.
-
-The user LED is simultaneously toggled at the usual $\frac{1}{2}~\text{Hz}$.
-
-The `led_rgb_ws2812` template class can be found in its entirety in the file
-[`mcal_led_rgb_ws2812.h`](./src/mcal/avr/mcal_led_rgb_ws2812.h).
-
-The template signature of the `led_rgb_ws2812` template class is shown
-in the declaration below.
-
-```cpp
-  namespace mcal { namespace led {
-
-  template<const std::uint8_t PortAddr,
-           const std::uint8_t PortBpos,
-           const unsigned LedCount = static_cast<unsigned>(UINT8_C(1))>
-  class led_rgb_ws2812;
-} } // namespace mcal::led
-```
-
-The first two template parameters `PortAddr` and `PortBpos`
-are used to set the port address and bit position of the digital I/O port.
-These very specific mcal/microcontroller-dependent parameters
-are used to generate the real-time ws2812 control signal.
-
-The third template parameter `LedCount` provides the ability
-to link multiple ws2812 devices seqentially and control them
-in an LED chain, as is common for this particular device.
-
-In example chapter09_08a, a ws2812 LED device is used.
-
-### Enhanced RGB-Color-Light-Show
-
-The RGB-color-light-show in example chapter09_08a (this example)
-differs slightly from the one in example chapter09_08 (the previous example).
-
-In this example the color transitions are a bit lenghtier in time
-(instead of the normal $20~\text{ms}$). Also the color transitions
-at and around the points $255~\text{bits}$-RGB
-have been lengthened in time. This results in color emphasis
-near these points.
-
-This enhanced RGB-color-light-show can be found in the file
-[`app_led.cpp`](./src/app/led/app_led.cpp).
-
-### Windows Simulation
-
-The chapter09_08a Win32-API simulation in its Windows-based
-application is shown in action in the image below.
-
-![](./images/rgb_led_wnd_09_08a.jpg)
+Example chapter09_08b utilizes essentially the same techniques
+to control its ws2812 RGB LED as were used in Example Chapter09_08a.
+In variation 09_08b, however, a 32-bit, single-core ARM(R) Cortex(R)-M3
+microcontroller is used.
 
 ## Hardware Setup
 
-In this particular example, we have simply used a commercially-available
-ARDUINO(R) placed on a breadboard with soldered-on pins.
-The wiring is straightforward. The ws2812 port control uses port pin `portd.3`.
-
-The hardware setup with the RGB LED in action is pictured
-in the images below. The pictures show colorful RGB hues eminating
-from the bright RGB LED of type ws2812.
-
-![](./images/board09_08a_01r.jpg)
-![](./images/board09_08a_02g.jpg)
-![](./images/board09_08a_03b.jpg)
-
-### Bit Timing: ws2812
-
-The approximate bit timing needed by the ws2812 is shown in the following table.
-
-| Bit Value | $T_{hi}~\left[{ns}\right]$ | $T_{lo}~\left[{ns}\right]$ |
-| --------- | --------------- | --------------- |
-|    $0$    |    $350$        |    $800$        |
-|    $1$    |    $700$        |    $600$        |
-
-A sample partial-trace of the control signal on `portd.3` is shown
-below in a representation of an image from a digital oscilloscpoe.
+In this particular example, we have simply used
+the commercially-available, open-platform
+[STM32F100 Value Line Discovery Kit](https://www.st.com/en/evaluation-tools/stm32vldiscovery.html)
+with soldered-on pins fitted on a breadboard.
 
-![](./images/ws2812_signal.jpg)
+The wiring is straightforward. The blinking LED uses the blue colored
+user LED controlled by pin `portc.8`. The LED digital control signal
+is on `portb.9`. The microcontroller is clocked at $24~\text{MHz}$.