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Speed control using PWM and the L293D Driver — Parallax Forums

Speed control using PWM and the L293D Driver

blueiceblueice Posts: 12
edited 2005-01-31 15:26 in BASIC Stamp
I was just looking up on controlling the speed of my motor using the L293D...(ive used the driver chip for normal on and off motor projects)

Do i use the BS2's PWM command to run it?
Also ,how do i go about connecting it to the driver chip..
My idea is this...
2 pins from the BS2 to the·input pins of the 293D
The PWM pin to the driver chip's Enable line..

Is this correct..
Thank you for ur time...



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**·ice**

Gerard Sequeira
Machinegrid.com·:: Robots at Work!!
Parallel Port Tutorials,
Autonomous Robots,
PIC16F84a Temperature Controller
·

Comments

  • Jon WilliamsJon Williams Posts: 6,491
    edited 2005-01-20 14:27
    The BASIC Stamp's PWM instruction is actualy designed to charge an RC circuit to a desired level -- to create an analog voltage output. This circuit is buffered so the instruction doesn't run constantly.

    If you look at our NX-1000-24/40 documenation you'll see a way to synthesize PWM to a motor controller, though it may not fit your needs. Beyond that, we offer a product called the PWMPAL which does produce PWM waveforms suitable fro driving motors.

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    Jon Williams
    Applications Engineer, Parallax
    Dallas, TX· USA
  • blueiceblueice Posts: 12
    edited 2005-01-20 17:22
    Thank Jon,
    but whats the· NX-1000-24/40 documenation ,can you post a link


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    **·ice**

    Gerard Sequeira
    Machinegrid.com·:: Robots at Work!!
    Parallel Port Tutorials,
    Autonomous Robots,
    PIC16F84a Temperature Controller
    ·
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2005-01-20 18:24
    Sure ... and I suggest you spend some time poking around our site too; lots of interesting stuff and the Search tool can usually help you locate something (I used it to find this link for you):

    http://www.parallax.com/dl/docs/prod/boards/28137.pdf

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    Jon Williams
    Applications Engineer, Parallax
    Dallas, TX· USA
  • blueiceblueice Posts: 12
    edited 2005-01-31 05:47
    Ok..i used the PWM example featured in the documentation..
    However i cannot get a higher frequency from the BS2 .The motor starts jerking at low frequencies..
    i need around 5Khz and i think yhe BS2 can output a· max of 1Khz,[noparse][[/noparse]a pause of 1ms]

    Is there a solution other than using the PWMpal..like using· a
    BS2-DAC-555 timer..
    anyone tried it before..







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    **·ice**

    Gerard Sequeira
    Machinegrid.com·:: Robots at Work!!
    Parallel Port Tutorials,
    Autonomous Robots,
    PIC16F84a Temperature Controller
    ·
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2005-01-31 15:26
    Try PAUSE 0 -- it's legal.

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    Jon Williams
    Applications Engineer, Parallax
    Dallas, TX· USA
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