Add initial documentation

API.md

@@ -0,0 +1,131 @@
+# LoRa API
+
+## Include Library
+
+```arduino
+#include <LoRa.h>
+```
+
+## Setup
+
+### Begin
+
+Initialize the library with the specified frequency.
+
+```arduino
+LoRa.begin(frequency);
+```
+ * `frequency` - frequency in Hz (`433E6`, `866E6`, `915E6`)
+
+Returns `1` on success, `0` on failure.
+
+## Set pins
+
+Override the default `NSS` and `NRESET` pins used by the library. **Must** be called before `LoRa.begin()`.
+
+```arduino
+LoRa.setPins(ss, reset);
+```
+ * `ss` new slave select pin to use, defaults to `10`
+ * `reset` new reset pin to use, defaults to `9`
+
+### End
+
+Stop the library
+
+```arduino
+LoRa.end()
+```
+
+## Sending data
+
+### Begin packet
+
+Start the sequence of sending a packet.
+
+```arduino
+LoRa.beginPacket();
+```
+
+Returns `1` on success, `0` on failure.
+
+### Writing
+
+Write data to the packet. Each packet can contain up to 255 bytes.
+
+```arduino
+LoRa.write(byte);
+
+LoRa.write(buffer, length);
+```
+* `byte` single byte to write to packet
+
+or
+
+* `buffer` data to write to packet
+* `length` size of data to write
+
+Returns the number of bytes written.
+
+**Note:** Other Arduino `Print` API's can also be used to write data into the packet
+
+### End packet
+
+End the sequence of sending a packet.
+
+```arduino
+LoRa.endPacket()
+```
+
+Returns `1` on success, `0` on failure.
+
+## Receiving data
+
+### Parsing packet
+
+Check if a packet has been received.
+
+```arduino
+int packetSize = LoRa.parsePacket();
+```
+
+Returns the packet size or `0` if no packet was received.
+
+### Packet RSSI
+
+```arduino
+int rssi = LoRa.packetRSSI();
+```
+
+Returns the RSSI of the received packet.
+
+### Available
+
+```arduino
+int availableBytes = LoRa.available()
+```
+
+Returns number of bytes available for reading.
+
+### Peeking
+
+Peek at the next byte in the packet.
+
+```arduino
+byte b = LoRa.peek();
+```
+
+Returns the next byte in the packet or `-1` if no bytes available.
+
+### Reading
+
+Read the next byte from the packet.
+
+```arduino
+byte b = LoRa.read();
+```
+
+Returns the next byte in the packet or `-1` if no bytes available.
+
+**Note:** Other Arduino [`Stream` API's](https://www.arduino.cc/en/Reference/Stream) can also be used to read data from the packet
+