USBHostSerial

Table of Contents

  1. Hello World
  2. API
  3. Related

mbed OS 2 and mbed OS 5

This is the handbook for mbed OS 2. If you’re working with mbed OS 5, please see the new handbook and API References.

The USBHostSerial interface is used to communicate with a virtual serial port usb device.

Library in Beta!

This library is in Beta. If you have any problems using the USBHost library, please send a bug report at support@mbed.org

The USB Host connector should be attached to

  • p31 (D+), p32 (D-) and GND for the LPC1768
  • add two 15k resistors tied to GND on D+ and D-

Hello World

Import program

00001 #include "mbed.h"
00002 #include "USBHostSerial.h"
00003 
00004 DigitalOut led(LED1);
00005 Serial pc(USBTX, USBRX);
00006 
00007 void serial_task(void const*) {
00008     USBHostSerial serial;
00009     
00010     while(1) {
00011     
00012         // try to connect a serial device
00013         while(!serial.connect())
00014             Thread::wait(500);
00015         
00016         // in a loop, print all characters received
00017         // if the device is disconnected, we try to connect it again
00018         while (1) {
00019         
00020             // if device disconnected, try to connect it again
00021             if (!serial.connected())
00022                 break;
00023 
00024             // print characters received
00025             while (serial.available()) {
00026                 printf("%c", serial.getc());
00027             }
00028             
00029             Thread::wait(50);
00030         }
00031     }
00032 }
00033 
00034 int main() {
00035     Thread serialTask(serial_task, NULL, osPriorityNormal, 256 * 4);
00036     while(1) {
00037         led=!led;
00038         Thread::wait(500);
00039     }
00040 }

API

Import libraryUSBHost

No documentation found.

Troobleshooting

If your mbed board is automatically resetted when you plug a USB device, you should consider to use an external power supply