Adds a README.

README.md

@@ -1,6 +1,61 @@
 # Kidsbox
 
-### RFID
+This is a battery-powered rfid-tag-controlled audio player meant to be used by kids.
+You can bundle audio-files to rfid tags and let your kids choose the music or audiobook of their favour by placing the corresponding tag atop of the box.
+
+## Todo
+
+- Volume buttons
+- Playlists
+- Pausing
+- ... I have a lot of ideas :)
+
+## Setup
+
+1. Install ESP-ADF and ESP-IDF according to the [install guide](https://docs.espressif.com/projects/esp-adf/en/latest/get-started/index.html#installation-step-by-step).
+2. Clone this repository and `cd` into the repository directory.
+3. `git submodule init --recursive`
+3. `cd device`
+4. Make sure that you have `idf.py` available in your environment. This is described in the install guide.
+5. Execute `idf.py build` to compile, `idf.py build flash monitor` to flash it to your board.
+
+## Hardware
+
+### Parts
+
+_TBD_
+
+|Part|Links|
+|-|-|
+|ESP32-LyraT 4.3|[Mouser](https://www.mouser.de/ProductDetail/Espressif-Systems/ESP32-LyraT?qs=MLItCLRbWsxPzPCja546ZA%3D%3D)|
+
+
+### Hardware Setup
+
+The peripherals must be configured for:
+
+- SD Card
+- RFID-module
+- Vol+/- buttons 
+
+The ESP32-LyraT board has only a few exposed GPIO pins. To save pins, the SD-Card reader runs only in 1-Wire mode. I have actually no idea what the limitations and differences are, but I didn't encounter any problems yet.
+
+#### DIP-Switch
+
+The switches must be exatly in the positions outlined in the table.
+
+|Number|Setting|Purpose|
+|-|-|-|
+|1|OFF|Disconnects GPIO 12 from SD-D2|
+|2|OFF|Disconnects GPIO 13 from SD-D3|
+|3|OFF|Connects GPIO 15 to SD CMD|
+|4|ON|Connects GPIO 13 to the JTAG header|
+|5|ON|Connects GPIO 12 to the JTAG header|
+|6|OFF|Connects GPIO 13 to SD CLK|
+|7|OFF|Disconnects GPIO 12 from the AUX-in-detection|
+|8|OFF| - |
+
+#### RFID
 
 _The MISO/MOSI pins are not inverted on host/chip_
 
@@ -11,7 +66,7 @@ Connection Table:
 |3.3v|3.3v|-|
 |RST|3.3v|-|
 |GND|GND|-|
-|SDA|SCLK|5|
-|SCK|SCK (I2C header)|23|
-|MOSI|LRCK|25|
-|MISO|DSDIN|26|
+|SDA|I2C SDA|18|
+|SCK|I2C SCL|23|
+|MOSI|JTAG MTCK|13|
+|MISO|JTAG MTDI|12|