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I/O Expansion Of 16f877a

Discussion in 'Microcontrollers, Programming and IoT' started by kasuncharya, Jan 26, 2012.

  1. kasuncharya


    Jan 25, 2012
    For my project I want around 50 I/O pins, how can I expand I/O pins.
    As I know it can be done I2C or 74573 latch IC.

    If somebody have experience of this matter please publish diagrams and codes (I use MikroC).

    I want to drive 7 stepper motors, dual line LCD module and one port for Inputs.
  2. jackorocko


    Apr 4, 2010
  3. OLIVE2222


    Oct 2, 2011
  4. kasuncharya


    Jan 25, 2012
    Thanks all and ......

    Thanks all and ......,I want MikroC code for I/O expansion ,It may be MCP23016 or Shift register.

    I read the MikroC I2C library, but how can a stepper motor pulse sequences insert into it.

    Simply stepper motor driving is not like LED matrix display.Can someone explain me how to do those steps.

    Pls post If you have project examples or any other explanations.
  5. Balrock


    Mar 1, 2012
    MikroE also do a stepper motor driver board. It is basically a darlington array. That will take care of the higher current requirements. Then look at their code for PWM (Pulse Width Modulation). They have lots of documentation on it with code examples. Look in the mikroC pdf and the help file. Most of all take your time to learn each part.

    If I am talking nonsense someone please say as I am also quite new to all this. Just trying to help out!
  6. TedA


    Sep 26, 2011

    Have you considered using a second PIC microcontroller to provide the extra I/O you require? Either another PIC18F877A, or another from the same family. The PICs can talk to each other using the I2C or SPI bus.

    It is possible your project might benefit from having a second processor, anyway, and the cost will not be much or any greater than that of I/O expanders only. If your project is going to have many time-critical functions, you might even go for more than two PICs.

    The most practical approach will depend on how many systems you expect to build to this design. If only one, you should attempt to make the construction and programming as easy as possible. If you are going to manufacture a million of them, you can afford to attempt to fit the quart of function into a pint of hardware.

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