Add DISCO_L475VG_IOT01A in README

Author: bcostm

README.md

@@ -28,6 +28,7 @@ In order to use BLE in mbed OS you need one of the following hardware combinatio
 
 * A Nordic nRF51-based board such as [nrf51dk](https://www.nordicsemi.com/eng/Products/nRF51-DK) or [mkit](https://www.nordicsemi.com/eng/Products/Bluetooth-R-low-energy/nRF51822-mKIT).
 * A supported target, such as the [NUCLEO-F401RE](http://www.st.com/en/evaluation-tools/nucleo-f401re.html), with a BLE shield or an external BLE peripheral, such as an [ST shield](http://www.st.com/web/catalog/tools/FM116/SC1075/PF260517).
+* A [DISCO_L475VG_IOT01A (ref B-L475E-IOT01A)](http://www.st.com/en/evaluation-tools/b-l475e-iot01a.html) board.
 
 
 The [`ble`module](https://github.com/ARMmbed/mbed-os/tree/master/bluetooth/ble) provides the BLE APIs on mbed OS.
@@ -45,6 +46,9 @@ The following targets have been tested and work with these examples:
 	* K64F
 	* NUCLEO_F401RE
 
+* STMicroelectronics:
+	* DISCO_L475VG_IOT01A (ref B-L475E-IOT01A)
+
 	<span> **Important:** if an ST shield is used with the K64F board, an hardware is patch required. Check out https://developer.mbed.org/teams/ST/code/X_NUCLEO_IDB0XA1/ for more information.</span>
 
 ### Using ST Nucleo shield on other targets