Update README.md

Author: ABOSTM

README.md

@@ -1,2 +1,35 @@
 # ST25DV
-Arduino library to support ST25DV components
+Arduino library to support the NFC ST25DV components:
+ * ST25DV04K
+ * ST25DV64K
+
+## API
+
+This NFC sensor uses I2C to communicate.
+It creates the instance st25dv.
+
+It is then required to call begin API with the 2 pins to be used before accessing to the sensors, and optionally wire instance:
+    `    st25dv->begin(gpo_pin, lpd_pin);`
+or
+```
+    TwoWire MyWire(SDA_PIN, SCL_PIN);
+    st25dv->begin(gpo_pin, lpd_pin, MyWire);
+```
+
+
+It is then possible to read/write NFC URI:
+
+```
+    int writeURI(String protocol, String uri, String info);
+    String readURI();
+```
+
+
+## Documentation
+
+You can find the source files at
+https://github.com/stm32duino/ST25DV
+
+The ST25DV datasheets are available at
+https://www.st.com/content/st_com/en/products/nfc/st25-nfc-rfid-tags-readers/st25-dynamic-nfc-tags/st25dv-i2c-series-dynamic-nfc-tags/st25dv04k.html
+https://www.st.com/content/st_com/en/products/nfc/st25-nfc-rfid-tags-readers/st25-dynamic-nfc-tags/st25dv-i2c-series-dynamic-nfc-tags/st25dv64k.html