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Simple PWM

userc_38527 Feb 22, 2013 7:07 AM

Guys,

Anyone know how to create a pulse for PWM, on a simple way ?

thanks

1. Re: Simple PWM

userc_38527 Feb 10, 2013 11:53 AM (in response to userc_38527)

and how to use timer for it ?

in MCS51 :

void delay_us (void) //100us delay on 12Mhz
{
    TH0=0;
    TL0=0;
    TH0 = 0xFF;
    TL0 = 0x37;
    TR0 = 1;
    while(!TF0);
    TR0 = 0;
    TF0 = 0;
    return;
}

How can I create this on Cypress PSOC 1 ?



thanks
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2. Re: Simple PWM

JoMe_264151 Feb 10, 2013 12:09 PM (in response to userc_38527)

Easiest would be to use a PWM - Component and configure it accordingly. Have a look at the PWM's datasheet.

The way you showed in your example differs a bit from the way PSoCs work: Usually you do not need to access ports or pins directly, there are many pre-defined components: timers, PWM, counter, interfaces and you just have to configure them at design-time and start them with an API at run-time preferrably in c-language.



Bob
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3. Re: Simple PWM

DaKn_263916 Feb 10, 2013 12:48 PM (in response to userc_38527)

Some possibilities(besides the basic PWM module) -



http://www.cypress.com/?rID=2801



http://www.planetpsoc.com/component/content/article/71-prs-pwm.html



and the basic modules in Designer IDE (see lower right) -







Regards, Dana.
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4. Re: Simple PWM

DaKn_263916 Feb 10, 2013 12:50 PM (in response to userc_38527)
Pic attached.

Regards, Dana.

PSOC 1 PWMs and Timers.jpg 290.7 K
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5. Re: Simple PWM

userc_38527 Feb 10, 2013 9:10 PM (in response to userc_38527)
I have a chip level diagram as in the picture..

How can I connect the PWM ? for pinout, for example I wanna use P0.4 as an output to my motor.

Please find my capture attached

pwm.jpg 497.9 K
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6. Re: Simple PWM

rajivv_36 Feb 10, 2013 9:39 PM (in response to userc_38527)
In the parameters window of PWM8 user module, set the "compare out" as Row0_Output0. Then, click on LUT on that row and click on the buffer which connects to GlobalOutEven4 (GOE 4). Then click on globalOutEven4 line and select the "pin" as P0[4].

Please see attached PDF file for example.



-Rajiv Badiger

Digital routing.pdf 818.4 K
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7. Re: Simple PWM

ArvindK_86 Feb 11, 2013 1:49 AM (in response to userc_38527)

The simplest way to see a PWM signal on your pin is using the PWM usermodule.



Place it in your project, configure the signal timing/duty using the usermodule parameters window (refer to the PWM datasheet for info on this; right click on the PWM block -> Datasheet)



Configure output as Rajiv mentioned; easier way is to do it graphically:

Hold Shift key and click on the "CompareOut" terminal, then click on the Pin of your choice.



Only code that you need to add in your main.c is PWM8_Start(); (PWM8 is the name of the usermodule, change accordingly)





Regards,

Arvind
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8. Re: Simple PWM

userc_38527 Feb 14, 2013 7:47 PM (in response to userc_38527)

Ok, I'll try and get back to you guys later,

thanks for helping
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9. Re: Simple PWM

userc_38527 Feb 14, 2013 7:56 PM (in response to userc_38527)

What's "LUT" ?
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10. Re: Simple PWM

DaKn_263916 Feb 14, 2013 9:14 PM (in response to userc_38527)

Look Up Table



http://en.wikipedia.org/wiki/Lookup_table



Regards, Dana.
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11. Re: Simple PWM

DaKn_263916 Feb 14, 2013 9:21 PM (in response to userc_38527)

Click on LUT at end of ROW out, RO0(0) and this pops up







Regards, Dana.
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12. Re: Simple PWM

DaKn_263916 Feb 14, 2013 9:26 PM (in response to userc_38527)

Here are basic short videos to learn how to do HW routing and

a lot of other stuff for PSOC 1 -



http://www.cypress.com/?rID=40543



Regards, Dana.
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13. Re: Simple PWM

userc_38527 Feb 15, 2013 2:50 AM (in response to userc_38527)
I tried like in the captured picture, is it right ?

What's the period and pulse width for it ?

thanks

pwm3.jpg 427.2 K
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14. Re: Simple PWM

DaKn_263916 Feb 15, 2013 5:11 AM (in response to userc_38527)

From the data sheet (right click component and select data sheet )



TOUT = (PeriodValue+1)/FCLOCK


FOUT = FCLOCK/(PeriodValue+1)



The duty cycle equation also in datasheet.



And you should set a couple more properties. Note in datasheet are API f()

calls you can make to control PWM in software, like set period and dutycycle,

and to start the PWM.



Regards, Dana.
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