add epd2in13bc to README and add some comments to example

README.md

@@ -46,6 +46,7 @@ epd.update_and_display_frame( & mut spi, & display.buffer()) ?;
 | [4.2 Inch B/W (A)](https://www.waveshare.com/product/4.2inch-e-paper-module.htm) | Black, White | ✕ | Not officially [[2](#2-42-inch-e-ink-blackwhite---partial-refresh)] | ✔ | ✔ |
 | [1.54 Inch B/W (A)](https://www.waveshare.com/1.54inch-e-Paper-Module.htm) | Black, White | ✕ | ✔ | ✔ | ✔ |
 | [2.13 Inch B/W (A) V2](https://www.waveshare.com/product/2.13inch-e-paper-hat.htm) | Black, White | ✕ | ✔ | ✔  | ✔  |
+| [2.13 Inch B/W/R (B/C) V2](https://www.waveshare.com/product/raspberry-pi/displays/e-paper/2.13inch-e-paper-hat-b.htm) | Black, White, Red | ✕ | ✕ | ✔  | ✔  |
 | [2.9 Inch B/W (A)](https://www.waveshare.com/product/2.9inch-e-paper-module.htm) | Black, White | ✕ | ✔ | ✔ | ✔ |
 | [2.9 Inch B/W V2 (A)](https://www.waveshare.com/product/2.9inch-e-paper-module.htm) | Black, White | ✕ | ✔ | ✔ | ✔ |
 | [1.54 Inch B/W/R (B)](https://www.waveshare.com/product/modules/oleds-lcds/e-paper/1.54inch-e-paper-module-b.htm) | Black, White, Red | ✕ | ✕ | ✔ | ✔ |

examples/epd2in13bc.rs

@@ -23,6 +23,17 @@ use linux_embedded_hal::{
 // activate spi, gpio in raspi-config
 // needs to be run with sudo because of some sysfs_gpio permission problems and follow-up timing problems
 // see https://github.com/rust-embedded/rust-sysfs-gpio/issues/5 and follow-up issues
+//
+// This example first setups SPI communication using the pin layout found
+// at https://www.waveshare.com/wiki/2.13inch_e-Paper_HAT_(B). This example uses the layout for the
+// Raspberry Pi Zero (RPI Zero). The Chip Select (CS) was taken from the ep2in9 example since CE0 (GPIO8) did
+// not seem to work on RPI Zero with 2.13" HAT
+//
+// The first frame is filled with four texts at different rotations (black on white)
+// The second frame uses a buffer for black/white and a seperate buffer for chromatic/white (i.e. red or yellow)
+// This example draws a sample clock in black on white and two texts using white on red.
+//
+// after finishing, put the display to sleep
 
 fn main() -> Result<(), std::io::Error> {
     let busy = Pin::new(24); // GPIO 24, board J-18
@@ -104,7 +115,8 @@ fn main() -> Result<(), std::io::Error> {
         .into_styled(PrimitiveStyle::with_stroke(Black, 1))
         .draw(&mut display);
 
-    // draw white on Red background
+    // draw text white on Red background by using the chromatic buffer
+
     let _ = Text::new("It's working-WoB!", Point::new(90, 10))
         .into_styled(text_style!(
             font = Font6x8,

src/epd2in13bc/mod.rs

@@ -1,4 +1,6 @@
 //! A simple Driver for the Waveshare 2.13" (B/C) E-Ink Display via SPI
+//! More information on this display can be found at the [Waveshare Wiki]:(https://www.waveshare.com/wiki/2.13inch_e-Paper_HAT_(B))
+//! This driver was build and tested for 212x104, 2.13inch E-Ink display HAT for Raspberry Pi, three-color, SPI interface
 //!
 //! # Example for the 2.13" E-Ink Display
 //!
@@ -67,7 +69,7 @@ use crate::traits::{
 pub const WIDTH: u32 = 104;
 /// Height of epd2in13bc in pixels
 pub const HEIGHT: u32 = 212;
-/// Default background color (white) of epd2in9bc display
+/// Default background color (white) of epd2in13bc display
 pub const DEFAULT_BACKGROUND_COLOR: Color = Color::White;
 
 const NUM_DISPLAY_BITS: u32 = WIDTH * HEIGHT / 8;