Hi,
I am working with a board that uses an NXP LPC1837 and want to get the USB VCOM port working.
I downloaded the example (RTOSTutorial_Ex10A-LPC18xx) for the LPC1857 and modified it to match my hardware. ( took out the graphics controller, changed the USART from 3 to 0. Pulled USB1 from the run time environment. Removed SPI. Changed the CPU to LPC1837. Updated the pinouts in RTE_Device.h... I am not using PPWR, PWR_FAULT, and INDI1 on this USB port. )
It compiles and downloads OK. The calls to USBD_Initialize() and USBD_Connect() return usbOK.
However when I plug into a Windows 7 or Windows 10 PC nothing happens in device manager. Even if I have the driver wrong I should see something happen when I attach the board. I did go ahead and install the VCOM driver that was included with the example.
Anyway, I am using the same 12MHz crystal as on the demo board and the USB0 is pretty vanilla. Not much to customize.
I know my hardware works as I can install and run a Mass storage device demo that NXP makes available for USB0 on this part.
So I am not sure where to look next... is there an update to the VCOM example for this part? Did I forget something. I am using uVision 7.20.0.0. I have read most of the literature on CDC ATM and the example program... will spend the rest of today looking for something that I may have missed.
Thanks
Why don't you use example for MCB1800 board as your starting point?
c:\Keil\ARM\PACK\Keil\LPC1800_DFP\2.6.0\Boards\Keil\MCB1800\Middleware\USB\Device\VirtualCOM\
Thanks John and Milorad... I'll try changing my starting point and if that does not work will look into trying some of the tools on the Linux platform to debug.
Tony
I think I was using the recommended starting example after all. I got to it from a link in the RTOS tutorial so I labeled it accordingly. Anyway, I downloaded the example again just to be sure and edited it to remove the graphics and second USB.
I had fooled myself last time thinking that the USBD_Configured() call was returning GOOD. I had forgotten to turn optimization off and it appeared that the branch was taken when stepping in the debugger.
So now I can see that USBD_Initialize(0) and USBD_Connect(0) are returning GOOD. However USBD_Configured(0) never returns TRUE.
I should get this even if the USB cable is not connected, right?
So I am going to study the evaluation board schematics and try to see if anything on my hardware is different in a way that would prevent the example from working. ( my hardware works, I can run a mass storage example that NXP provides and I can ( with a boot jumper ) make the NXP bootloader work on USB0.
Any ideas would be appreciated. Also can you verify that USBD_Configured(0) should return TRUE even if I don't connect the USB cable? That would remove the PC configuration from the equation.
Thanks, Tony
I think I have it.
My board is a USB DEVICE and to be safe I resistor divided the 5V USB_VBUS before it connects to the processor. The board was built with the wrong divider resistors and the CPU never saw a HIGH on USB_VBUS.
I jumpered the divider out and it seems to be working. Guess the NXP driver does not care about the USB_VBUS input.