Add ability to set MAC address to custom value

Author: kegilbert

platform/mbed_interface.c

@@ -81,6 +81,14 @@ WEAK int mbed_uid(char *uid) {
 }
 #endif
 
+static uint8_t manual_mac_address_set = 0;
+static char manual_mac_address[6];
+
+void mbed_set_mac_address(const char *mac) {
+    memcpy(manual_mac_address, mac, 6);
+    manual_mac_address_set = 1;
+}
+
 WEAK void mbed_mac_address(char *mac) {
 #if DEVICE_SEMIHOST
     char uid[DEVICE_ID_LENGTH + 1];
@@ -101,12 +109,16 @@ WEAK void mbed_mac_address(char *mac) {
         mac[0] &= ~0x01;    // reset the IG bit in the address; see IEE 802.3-2002, Section 3.2.3(b)
     } else {  // else return a default MAC
 #endif
+    if(manual_mac_address_set) {
+        memcpy(mac, manual_mac_address, 6);
+    } else {
         mac[0] = 0x00;
         mac[1] = 0x02;
         mac[2] = 0xF7;
         mac[3] = 0xF0;
         mac[4] = 0x00;
         mac[5] = 0x00;
+    }
 #if DEVICE_SEMIHOST
     }
 #endif

platform/mbed_interface.h

@@ -98,6 +98,15 @@ int mbed_interface_uid(char *uid);
 
 #endif
 
+/** This provides a generic function to set a unique 6-byte MAC address based on the passed
+ *  parameter character array. Provides no MAC address validity checking
+ *  
+ *  mbed_mac_address() will readback this configured value
+ *
+ *  @param mac A 6-byte array containing the desired MAC address to be set
+ */
+void mbed_set_mac_address(const char *mac);
+
 /** This returns a unique 6-byte MAC address, based on the interface UID
  * If the interface is not present, it returns a default fixed MAC address (00:02:F7:F0:00:00)
  *