Comples PWM calculation

[David VB]

Hi there,

I have to compute a PWM value (PWMcal) (on 10 bits), depending on 4 values:

• PWMprg = Value asked by the program [0..1023]
• VALamb = Value of an LDR (from ADC) [0..1023]
• PWMmax and PWMmin = values between which the final value (PWMcal) must be proportional to and within those two boundaries [PWMmin..PWMMax].  Those boundaries are word constants.

Examples: 

• If PWMprg = 0 and VALamb=0, then PWMcal=PWMmin
• if PWMprg = 512 and VALamb = 512 then PWMcal=[(PWMmax-PWMmin)/1024]+PWMMin  (= Half Way between PWMmin and PWMmax)
• if PWMprg=1023 and VALamb=1023 then PWMcal=PWMmax

I'm not a genious on maths and can't make head or tales from it....

Any help welcome !

Thank you

David

[Rob CJ]

Hi David,

Just some thoughts.

I think it is the easiest if PWMmin = 0.

I then it has to be something like this: PWMcal =  ((VALamb * PRMprg) / (1023 * 1023)) * PWMmax

Kind regards,

Rob

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Van: jal...@googlegroups.com <jal...@googlegroups.com> namens David VB <pinhe...@gmail.com>
Verzonden: woensdag 3 december 2025 16:29
Aan: jallist <jal...@googlegroups.com>
Onderwerp: [jallist] Comples PWM calculation

 

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