Fix typos and add alt text for examples chapter09_08 a and b

Author: Alejandro-Casanova

examples/chapter09_08a/readme.md

@@ -1,4 +1,5 @@
 # Example Chapter09_08a
+
 ## Controlling an RGB LED of type ws2812
 
 Example chapter09_08a utilizes object oriented programming techniques
@@ -18,7 +19,7 @@ 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 for the target system as well as a simulated PC
 version are available. For this exercise, it was
 decided to implement a rather detailed PC simulation
 using old-school traditional Win32-API programming.
@@ -52,7 +53,7 @@ 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
+to link multiple ws2812 devices sequentially and control them
 in an LED chain, as is common for this particular device.
 
 In example chapter09_08a, a ws2812 LED device is used.
@@ -62,7 +63,7 @@ In example chapter09_08a, a ws2812 LED device is used.
 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
+In this example the color transitions are a bit lengthier 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
@@ -76,7 +77,7 @@ This enhanced RGB-color-light-show can be found in the file
 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)
+![Capture of Windows simulation](./images/rgb_led_wnd_09_08a.jpg)
 
 ## Hardware Setup
 
@@ -85,23 +86,23 @@ 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
+in the images below. The pictures show colorful RGB hues emanating
 from the bright RGB LED of type ws2812.
 
-![](./images/board09_08a_01r.jpg)
-![](./images/board09_08a_02g.jpg)
-![](./images/board09_08a_03b.jpg)
+![Hardware setup - magenta hue emanating from LED](./images/board09_08a_01r.jpg)
+![Hardware setup - green hue emanating from LED](./images/board09_08a_02g.jpg)
+![Hardware setup - cyan hue emanating from LED](./images/board09_08a_03b.jpg)
 
 ### Bit Timing: ws2812
 
 The approximate bit timing needed by the ws2812 is shown in the following table.
 
 | Bit Value | $T_{hi}~\left[{ns}\right]$ | $T_{lo}~\left[{ns}\right]$ |
-| --------- | --------------- | --------------- |
-|    $0$    |    $350$        |    $800$        |
-|    $1$    |    $700$        |    $600$        |
+| --------- | -------------------------- | -------------------------- |
+|    $0$    |                      $350$ |                      $800$ |
+|    $1$    |                      $700$ |                      $600$ |
 
 A sample partial-trace of the control signal on `portd.3` is shown
-below in a representation of an image from a digital oscilloscpoe.
+below in a representation of an image from a digital oscilloscope.
 
-![](./images/ws2812_signal.jpg)
+![View of trace captured on digital oscilloscope](./images/ws2812_signal.jpg)

examples/chapter09_08b/readme.md

@@ -1,4 +1,5 @@
 # Example Chapter09_08b (variation 32-bit microcontroller)
+
 ## Controlling an RGB LED of type ws2812
 
 Example chapter09_08b utilizes essentially the same techniques
@@ -20,7 +21,7 @@ A logic-AND gate shifts the microcontroller pin's voltage level.
 The microcontroller is clocked at $24~\text{MHz}$.
 
 The hardware setup with the RGB LED in action is pictured
-in the image below. The pictures depicts a pink hue eminating
+in the image below. The pictures depicts a pink hue emanating
 from the bright RGB LED of type ws2812B.
 
-![](./images/board09_08b.jpg)
+![Hardware setup - pink hue emanating from LED](./images/board09_08b.jpg)