USBHostSerial

Table of Contents

  1. Hello World
  2. API
  3. Related

mbed OS 2

This is the handbook for mbed OS 2.

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