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pwm wave of frequency 10hz from microcontroller ?

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jit_singh_tara

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pwm wave

hi can we produce pwm wave from uc of fixed frequency 10hz , not using timers but inbuilt pwm module .
issue is that since microcontroller is connected to external crystal , then is is possible to have a waveform as less as 10hz frequency.
 

10hz pwm

1. Why not continueing your own thread, this is basically the same question.
2, The question can't be answered generally. Depends strongly on microprocessor details, particularly availability of prescalers or to cascade timers.
3. A build-in PWM unit is just a timer with special features, thus it's nonsense to say not using timers.
 

what is pwm wave

I was used PIC with the following configuration :
- HW PMW module used
- Timer interrupt of 3840Hz@Xtal=20MHz.

But, if harmonic distorsion is not a big problem, you can easilly increase timer frequency to 10KHz. Notice that main program will suffer a drastic reduction of speed performance.

+++
 

timer frequency microcontroller

Hi!
Yes we can but that depends on the external crystal frequency. As already said by FvM that a PWM module is nothing but a timer with special features. So generally it can be said that it strongly depends upon the features of a particular microcontroller. e.g if you consider the LPC series of ARM7 microcontrollers from NXP then they can generate a 1Hz signal from even 60MHz because of the extremely versatile timers (32 bit prescaler+32 bit timer comparator).
Regards.
 
how we can generate frequency of 10hz

your better to use a 4mhz crystal and a set of nop
also connect up and down so you can trim the output time

nop is dependent on the external or even internal oscillator
a pic 84 nop lenght is 4/4 in us = 1 so each nop{no operation} is 1us
this way you can have it accurate to 1us easy... or 1 millionth part
with pic877 @ 20mhz to 200ns pic18F series 10ns or 1ns using doubler

here is a c code you can modify
shows how to use interrupt on port b for switches and buttons etc
 

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