SOFTWARE MODIFICATIONS

    Current software architecture:

    The Fotoman software architecture is based on: -

    • A boot code stored in the Fotoman ROM
    • The main code stored in the Fotoman RAM, known as FOTOWARE. This code operates the Fotoman, performs the data compression, and manages the communications with an external computer through a serial link.
    • The exploitation code, known as FOTOTOUCH, based on an external computer. This code contains a dialog/acquisition segment, an executable named FOTOMAN.EXE, and an image processing segment.
    • The native mode communication program TERM allowing the ASCII commands, used in commanding the Fotoman Plus, to be entered via the keyboard.

    Modification plan

    A special version of the FOTOWARE, currently in Beta test at Logitech, allows disabling of the flash, manual setting of the exposure time, and control of the battery counter. The battery counter is a model of the battery maintained by the FOTOWARE, which does not measure any physical quantity from the batteries. However, the battery counter must be above a certain level, before the Fotoman can take a picture.

    However, if the camera batteries are removed and replaced, the onboard software assumes that the replacement batteries are uncharged. As the power circuitry for the digital camera replaces the batteries, on power up, the counter will read zero and the camera will not be able to take a picture. By controlling the counter, we can change the erroneous indication of insufficient power, and take a picture immediately. Flash control is recommended, as the flash will be physically disabled.

    FOTOTOUCH or any other standard image manipulation package can be used in the ground station to view and process the images, which are downloaded in standard JPEG format.

    A full new software has to be implemented for dialog/acquisition within the spacecraft CPU, and interfaced/included into its main control module. This software must be able to perform the following tasks:

    • turn on/off the Fotoman Plus
    • upload FOTOWARE from the PROM into the Fotoman Plus RAM at a given time.
    • send orders to take pictures to the Fotoman.
    • request and receive status,contact, and image inventory information
    • retrieve pictures from the Fotoman, to be stored in the CPU, which will be sent at a later time to the ground station.

    These tasks can be performed using the 16 commands set of provided in the Native Mode Toolkit.

    Typical tasks for the FotoMan executable by SAPPHIRE would be:

    • take a picture at a given time (using the on-board clock)
    • download Picture #n stored in CPU memory

    Back to Digital Camera Page

    Back to Payload Subsystem Main Page

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