how to use this device to download the C pragramm?I do not know how to use this decice andshould I have to buy a miniprog to download?
This device is used to interface between PC and any PSoC with I2C protocol as means of communication protocol. However you will be able to download C Program provided your PSoC should contain I2C Bootloader function.
Please go through the application notes An2352 which explains how to use Cy3240.
Also for bootloader functionality go throughhttp://www.cypress.com/?rID=2904
For reference guide of the device :