This code will display two unsigned shorts (representing health & remaining ammo) on a TextLCD display. The mbed receives them via the USB HID interface.
Diff: main.cpp
- 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; + } +}