doc: Update README

- Improve format.
- Document API.

README.md

@@ -1,10 +1,8 @@
-node-pcsclite
-=============
+# node-pcsclite
 
 Bindings over pcsclite to access Smart Cards
 
-Installation
-============
+## Installation
 
 In order to install the package you need to have installed in the system the
 pcsclite libraries. In Debian/Ubuntu:
@@ -19,9 +17,9 @@ To run any code you will also need to have installed the pcsc daemon:
 
     apt-get install pcscd
 
-Example
-=======
+## Example
 
+```
 var pcsc = require('pcsclite');
 
 var pcsc = pcsc();
@@ -76,8 +74,78 @@ Example
 pcsc.on('error', function(err) {
     console.log('PCSC error', err.message);
 });
+```
+
+## API
+
+### Class: ChildProcess
+
+The PCSCLite object is an EventEmitter that notifies the existence of Card Readers.
+
+#### Event:  'error'
+
+* *err* `Error Object`. The error.
+
+#### Event:  'reader'
+
+* *reader* `CardReader`. A CardReader object associated to the card reader detected
+
+Emitted whenever a new card reader is detected.
 
 
+### Class: CardReader
 
-[![Bitdeli Badge](https://d2weczhvl823v0.cloudfront.net/santigimeno/node-pcsclite/trend.png)](https://bitdeli.com/free "Bitdeli Badge")
+The CardReader object is an EventEmitter that allows to manipulate a card reader.
 
+#### Event:  'error'
+
+* *err* `Error Object`. The error.
+
+#### Event:  'end'
+
+Emitted when the card reader has been removed.
+
+#### Event:  'status'
+
+* *status* `Object`.
+    * *state* The current status of the card reader as returned by `SCardGetStatusChange`
+    * *atr* ATR of the card inserted (if any)
+
+Emitted whenever the status of the reader changes.
+
+#### reader.connect(callback)
+
+* *callback* `Function` called when connection operation ends
+    * *error* `Error`
+    * *protocol* `Number` Established protocol to this connection.
+
+Wrapper around `SCardConnect`. Establishes a connection to the reader.
+
+#### reader.disconnect(callback)
+
+* *callback* `Function` called when disconnection operation ends
+    * *error* `Error`
+
+Wrapper around `SCardDisconnect`. Terminates a connection to the reader.
+
+#### reader.transmit(input, res_len, protocol, callback)
+
+* *input* `Buffer` input data to be transmitted
+* *res_len* `Number`. Max. expected length of the response
+* *protocol* `Number`. Protocol to be used in the transmission
+* *callback* `Function` called when disconnection operation ends
+    * *error* `Error`
+    * *output* `Buffer`
+
+Wrapper around `SCardTransmit`. Sends an APDU to the smart card contained in the reader connected to.
+
+#### reader.control(input, control_code, res_len, callback)
+
+* *input* `Buffer` input data to be transmitted
+* *control_code* `Number`. Control code for the operation
+* *res_len* `Number`. Max. expected length of the response
+* *callback* `Function` called when disconnection operation ends
+    * *error* `Error`
+    * *output* `Buffer`
+
+Wrapper around `SCardControl`. Sends a command directly to the IFD Handler (reader driver) to be processed by the reader.