please help...urgent case...

Discussion in 'Embedded Systems and Microcontrollers' started by cosgan, May 16, 2008.

  1. cosgan

    Thread Starter New Member

    May 16, 2008
    Hey guys, nice to know you all. im learning the embedded system and have the project below which i don't know how to start and do it. could someone help me on it?

    Overall objective of the project: To design and develop a data acquisition system.

    Using the features of the PIC18f452/4520 microcontroller and the associated Input/Output board available develop a system to sample and log analogue voltage readings at a specified frequency (in this case - 8 analogue inputs). For example very second.

    the system MUST use timer interrupts to ensure accurate and periodic sampling of the analogue voltage. If any of the input voltage exceeds 3.5V, the buzzer should be activated. The sampled data should be stored in memory for later download via RS232 to a PC.

    Additionally the data sampling could be made flexible and under user control. For example the sampling rate could be variable rather than fixed, or maybe selectable from a range of values.

    The sampling rate must be selectable and under user control.
    Design and show how the acquired data can be transferred to a PC and then made available on the screen display. E.g.dumb terminal display.

    ** Please help me...i'm interested with embedded system, and i wanna do further learning on it. with the help of you sir to help me produce the system, i would greatly appreciate it.
  2. Dave

    Retired Moderator

    Nov 17, 2003
    1. Get the datasheet for the said microcontroller from, familiarise yourself with the basic details of the device.

    2. Choose a language; ASM or C, C is probably best. Go to and download the C18 compiler (you may have this on disc from the uC package). Download the supporting documentation.

    3. Sit down with your list of specifications and the datasheet outline what aspects of the 18f452 are of use; the datasheet is broken down into appropriate sections. Conceptualise an architecture.

    These are the first steps to getting you started before you can even think about developing a solution.

  3. m.majid

    Active Member

    May 28, 2008
    you should specify more detailed characteristics of your project,
    for example :
    how much data samples required to be buffered until connect to pc?
    if you answer this question, you can choose appropriate memory chip for data logging.

    for communicating with pc, I propose you declare some instructions. PC can set configuration and get data from your system using that instructions.
    for example:
    set rate (set rate of sampling data into memory)
    get data (acquiring stored data from embedded system to PC)
    clear memory (clear stored data from memory of embedded system)
  4. nanovate

    Distinguished Member

    May 7, 2007
    Once you have sat down and completed the above tasks then tackle the project piece by piece. It seems daunting at first but just like eating a big sandwich you have to eat it one bite at time.