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Picture Transfer Protocol (PTP) / USB Still Image Capture Class Driver
Picture Transfer Protocol (PIMA 15740:2000, ISO 15740) is developed by I3A (International Imaging Industry Association) as a standard for exchanging images with and between digital still photography devices. In 2005, PTP has become an international standard as known as ISO 15740.
PTP protocol is independent from the transport medium, it can be implemented on any communication protocol including IRDA, USB, 1394. Recently an implementation of PTP working over IP (PTP/IP) has also been announced.
Since USB is very popular and user friendly many device manufacturers have implemented PTP protocol on USB. The devices that are using PTP over USB are implemented conforming to the "USB Still Image Capture Class" specification. This specification defines the details of how USB communication has to be done and how an imaging device has to present itself as a USB device.
We at Centrillium have developed a PTP device driver for our client which was one of the big players in the consumer electronics market. Our PTP driver is developed for pSOS operating system from Windriver Systems for MIPS16/32 platform, however it is portable to any embedded or desktop operating system. Our implementation consists of the following blocks:
PTP API
PTP Protocol Driver
USB Still Image Capture Class Driver
USB Still Image Capture Class Driver handles USB communication and provides a generic interface for sending and receiving PTP commands on USB. PTP protocol driver implements the commands and the communication flow at PTP level. PTP API provides an interface for the application programmer to access features of a imaging device using the PTP protocol. Such typical application maybe a software downloading pictures from a camera and displaying slide shows.
Our Offer
We are happy to share our experience and know-how on Picture Transfer Protocol and USB Still Image Capture Class devices and help you with your projects. Please don't hesitate to contacts us if you require more information: info@centrillium-it.com
