Bug in New Device First Page

03 Mar 2013

When I first plugged in my new mbed LPC11U24 and clicked on MBED.HTM, I was directed to a page that had a link to 'serial.zip' rather than 'mbedWinSerial_16446.exe'. When I used Serial.inf from the zip folder I got the new mbed LPC11U24 as drive, but not as a USB serial port.

Igor answered a question I posted relating to this problem, and gave me a link to the right Win driver, and when I used that I did get a USB serial port. I compiled and loaded the sample program USBserial_HelloWorld into the new mbed. I opened the new USB serial port with Tera Term, and hit Reset. I did not get the 'I am a virtual serial port!' message, but instead got a 'port pinout' error message and flashing LEDs.

I think by initially using the wrong driver I have dug myself into a hole, that I cannot get out of. So how do I now make a clean start, and make the demo program work?

I have tried several variations of the sample program, but cannot get messages out or command characters in.

03 Mar 2013

Not sure what may have happened with the wrong driver, but you should be able to delete it and reinstall. Do you see any problems (ie exclamation marks) in the windows device driverlist for the USB serial?

Are you compiling for the correct mbed type lpc11u24 rather than lpc1768? What is the name given to the bin? Where is the port pinout error message showing?

03 Mar 2013

I think I misunderstood what was meant by USB Serial, in thinking it meant communication through the main USB connector on the mbed LPC11U24. Instead it needs a connector tied directly to the D+ and D- pins on the module.

I have a CoolComponents mbed Workshop module that I used with my mbed LPC1768. It has a mini USB connector tied to the D pins. I dug that out plugged my mbed LPC11U24 into it and then connected a USB cable to the connector on the Workshop board.

Now Tera Term shows a long string of 'I am a virtual serial port!'

Not sure why or how this works, so I will study the schematic, and the library.

John

03 Mar 2013

USBSerial uses the serial port of the LPC as a virtual serial port. The USB connector of the mbed itself is connected to UART0 (via USB <> Serial conversion), so for that you can just use the normal serial class.

You need to log in to post a reply