This code will display two unsigned shorts (representing health & remaining ammo) on a TextLCD display. The mbed receives them via the USB HID interface.

Dependencies:   TextLCD

Revision:
0:36b4415952d0
diff -r 000000000000 -r 36b4415952d0 main.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Sun Dec 11 19:14:27 2011 +0000
@@ -0,0 +1,68 @@
+#include "mbed.h"
+#include "TextLCD.h"
+#include "USBHID.h"
+
+//for debugging
+Serial pc(USBTX, USBRX);
+
+//an LED to display activity
+DigitalOut hid_activity_led(LED2);
+DigitalOut alive_led(LED1);
+
+//The TextLCD
+TextLCD lcd(p21, p22, p17, p18, p19, p20); // rs, e, d4-d7
+
+//the mbed doesn't return the report ID.
+union hid_report_t {
+    uint8_t bytes[sizeof(int16_t)*2];
+    struct {
+        uint16_t health;
+        uint16_t ammo;
+    } data;
+};
+
+//We declare a USBHID device.
+// output report size = 1 (not needed here)
+// input report size matches the one defined above
+USBHID hid(sizeof(int16_t)*2, 1);
+
+//This report will contain data to be received
+HID_REPORT recv_report;
+
+int main() {
+    //initialise the LCD
+    lcd.printf("     CRYSIS\n  Maximum mbed");
+    pc.printf("ready!\r\n");
+    uint16_t health, ammo;
+    
+    while(1) {
+        if(hid.readNB(&recv_report)) {
+            pc.printf("recv[%d]: ", recv_report.length);
+            for(int i = 0; i < recv_report.length; i++) {
+                pc.printf("%d ", recv_report.data[i]);
+            }
+            pc.printf("\r\n");
+
+            //receive data
+            hid_report_t* pHidData = (hid_report_t*)(recv_report.data);
+            
+            //for some reason, the byte order has been changed!
+            //negative number support will need sign extension
+            health = __REV16(pHidData->data.health);
+            ammo = __REV16(pHidData->data.ammo);
+            
+            //for debugging...
+            //pc.printf("Health: %d, Ammo: %d\r\n", health, ammo);
+            //pc.printf("HEX: Health: %x, Ammo: %x\r\n", health, ammo);
+            
+            //write new values on screen.
+            lcd.cls();
+            lcd.printf("Health: %d\nAmmo: %d", health, ammo);
+            hid_activity_led = hid_activity_led == 0 ? 1 : 0;//show HID activity
+        }
+        
+        //toggle an LED to show us, that the mbed is alive.
+        wait(0.1);
+        alive_led = alive_led == 0 ? 1 : 0;
+    }
+}