Hello Srinivas,

Unfortunately AT43USB380 doesn't fit to '51.
It requires a dedicated API library on the MCU side. This API library is provided as an object format, not the source. And '51 is not included in the supported MCU.

Cypress SL811HS is available for '51 as CY3662- EZ-811HS dev.kit.
The firmware included in the dev.kit supports host stack, Hub and HID class, but printer class is not available. You'll need to make it by yourself.

USBWiz from GHI Electronics supports printer class for legacy unidirectional (SPP, Centronics) mode. Actually, this is enough.
http://www.ghielectronics.com/USBwiz.htm

As Russell pointed out, recent printers are graphic renderer, not character. They receives a page as a graphics. Considering the memory and process speed required, this approach doesn't fit to '51. But as many printers still support legacy SPP mode in the native font of the printer, they can be easily connected to '51 like dot matrix printers.

Read out the device ID string from your printer, and you'll know which protocol your printer supports. If your printer is connected to a PC over USB, you can read out the device ID string using USB sniffer utility, like

HHD USB monitor (trial): http://www.hhdsoftware.com/Products/...nitor.html
Snoopy Pro (free): http://sourceforge.net/projects/usbsnoop/

You'll find a string similar to these strings in this page, as a packet of Class-specific request, interface, index 0x100. (Get_Device_ID)
http://hpoj.sourceforge.net/doc/devic...trings.txt

To decipher CMD symbols, refer "Printing protocols" section of this page.
http://hpoj.sourceforge.net/hpoj-cvs/...ocols.html

Tsuneo