How to connect lpc3250 based OTG device(mini-AB receptale) to PC

[nightrapper]

Hi,

I am using LPC3250 board based on fdi3250 design and we are using mic2555 PHY for USB, board is having OTG connector to connect it with the PC.I am using linux 2.6.34 kernel version on the board.
I am having following queries
1.Does linux 2.6.34 have support for OTg for LPC3250?OTg files are there in the kernel tree.

2.I was reading through your article on "Create a USB Virtual COM Port" ,this provide a way to connect device having otg connector to PC.So according to article if i use FT232 chip we are connecting USB pins via  FT232 chip to Tx& Rx pins in controller,Since i am using LPC3250 controller supporting all modes (with inbuilt host/device/OTG controller),so how would be my connection,Do i have to run OTG module in UART mode and connect pins to UART?

3.If i connect my OTG device to another OTG device via min-a and mini-b cable will same connection work?

Please clarify my queries

[sudheerg_]

Hello,

1. I do not have any idea on this

2. In your case you need to implement CDC class in your firmware. When the Mini-B to Standard-A cable is connected between your devices and the PC then while sending device descriptors to Host PC you need to send CDC descriptors so that host understands them and loads a serial class driver on host side.

3. There are two chances, Mini-A connected to LPC3250 and Mini-B connected to another OTG Device X. In this case LPC3250 acts as Host and Device X acts as USB Device. The basic enumeration happens between LPC3250 and Device X (Like exchanging device descriptor and etc...).
In second case LPC3250 acts as device and X acts as USB Host.

Always remember that if your USB HW is Host it shall have the support for classes of devices that are connected to it. Similarly when your USB HW is acting as device then the host which is used to connect to it shall support the class supported by your USB HW.

Regards,
GSR

[nightrapper]

Thanks for the reply

But i need some clarity regarding the hardware connection.

Do we have to use micrel in UART mode as then it would be connected to the UART port of the controller with which we can establish communication or same USB mode connection would work with the these connection .

I am really confused on the hardware layout for it as the same micrel2555 chip can be used in both types of application (connected to OTG device or can be connected to PC).

[Tsuneo]

Hi nightrapper,
I'll answer just to your first question, because sudheerg_ is replying to others.

nightrapper
1.Does linux 2.6.34 have support for OTg for LPC3250?OTg files are there in the kernel tree.

Plain vanilla 2.6.34 doesn't support LPC3250 USB (especially, lpc32xx_udc.c). You'll need to apply this patch on LPCLinux ( http://www.lpclinux.com/Downloads/WebHome )

linux-2.6.34_lpc32x0-v1.10.patch.tar.bz2
ftp://ftp.lpclinux.com/lpc32x0/linux/linux-2.6.34/linux-2.6.34_lpc32x0-v1.10.patch.tar.bz2

lpc32xx_udc.c supposes ISP1301, discontinued, as its OTG PHY. MIC2555 is often mounted as its replacement. There are a couple of differences between ISP1301 and MIC2555.

http://www.lpcware.com/content/nxpfile/mic2555vsisp1301-connection-differences
http://www.lpcware.com/content/nxpfile/mic2555vsisp1301-usb-transceiver-differences

Tsuneo

[nightrapper]

sudheerg_  Sir
how to implement CDC class in my firmware.

I am having LPC3250 board based on fdi3250 design and we are using mic2555 PHY for USB, board is having OTG connector to connect it with the PC

Please  reply.

[nightrapper]

i have added patch file for micrel2555... now would it support otg for lpc3250 board

or should i use micrel2555 as serial mode to connect my otg connector on my device to pc

[Jan Axelson]

If you use an FT232, the CPU doesn't use USB port at all. It just communicates over the serial port, and the FT232 handles the USB protocols.