touch switch dimmer

hello everyone,
i am new in picbasic pro,recently i work on a project <touch switch dimmer>
i make 9 switches and connect them into pic 16f876,each output of the switch will give 0v or 5v.
1 switch is connected in portc.6 act as a selection button, when i touch it once,it control my LED brightness
second touch will goes to control my servo motor's speed

i arrange the rest of the 8 switches in circular shape and their output is connected to port B of my pic as a intensity controller. when i move clockwise, it will increase the brightness of the LED or the speed of the motor (depend on which 1 selected). If i move counter-clockwise,it will decrease the intensity.
and my output is pin CCP1 and CCP2,the output is connected to a RC filter then to the transistor and control the LED or the Motor circuit.
In this project, i try to use pwm to control the intensity,i need some idea to write the code...

before this,i try a code as below to test the pwm output,but it seem not work:
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' Output is a 1Khz signal with duty cycle sweeping
' from 20% to 80% once per second

' Note: PWM output will be on the CCP1 pin. Register
' names are for the PIC16F87x devices.

' PR2 = Timer2 period register, controls PWM period.
' CCPR1L and CCP1CON<5:4>bits control the duty cycle,
' and should be treated as a 10-bit word

' Fosc = Clock Frequency (4MHz)
' PS = Timer2 Prescale Value (T2CON<1:0>)
' Freq = PWM output frequency
' Duty% = Duty cycle (20% = 0.2)

' formulas:
' PR2=(Fosc/(4*PS*Freq))-1
' CCPR1L:CCP1CON<5:4>=(PR2+1)*4*Duty%

duty VAR WORD ' Duty cycle value (CCPR1L:CCP1CON<5:4>)


TRISC.2 = 0 ' Set PORTC.2 (CCP1) to output
CCP1CON = %00001100 ' Set CCP1 to PWM
T2CON = %00000101 ' Turn on Timer2, Prescale=4

' Use formula to determine PR2 value for a 1KHz signal,
' 4MHz clock, and prescale=4. (4E6/(4*4*1E3))-1=249

PR2 = 249 ' Set PR2 to get 1KHz out

' Use formula to determine CCPR1L:CCP1CON<5:4> value for
' ends of range 20% to 80%. (249+1)*4*0.2=200 (20% value)
' (249+1)*4*0.8=800 (80% value)


duty = 200 ' Set duty cycle to 20%

loop: CCP1CON.4 = duty.0 ' Store duty to registers as
CCP1CON.5 = duty.1 ' a 10-bit word
CCPR1L = DUTY >> 2

duty = duty + 10 ' Increase duty cycle

' Since the total sweep of duty is 600 (800-200) and
' we are adding 10 for each loop, that results in 60
' steps min to max. 1 second divided by 60 = 16.67mS

Pause 17 ' Pause 1/60 of second

IF (duty < 800) Then loop ' Do it again unless 80% duty cycle

duty = 200 ' Reset to 20% duty cycle

GoTo loop ' Do it forever

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thank for your helps

Quote:

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Originally Posted by helmut

before this,i try a code as below to test the pwm output,but it seem not work:

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Your code looks fine (to me) - what is not working?
Do you get PWM out? Is the timing off?
Is the 1 second off?
Anything connected to RC2 during this test?

i put a LED as the output in RC2
i c no different for the intensity of the LED after i run this pwm code....
did i missed some step?

You need to add DEFINE OSC 4, try with HPWM command.

thank you guys,i solve the pwm problems.that's minor mistake in my hardware.
In addtion, in my project, i move clockwise will increase intensity of my output.
and move counter clockwise will decrease the intensity.
so i try the shifting instruction
the code i used as shown:

if portb == portb>>1 then
high porta.0
endif
if portb == portb<<1 then
high porta.1
endif
end

if my 1st input is high in portb.0, it's consider shifting right or shifting left??