Some questions on motor speed control

[sayzer]

Hi everyone,
I'm starting to explore on motors specifically on 12v DC motor. Basically first I want to make it stop, turn it half speed and full speed using 10K resistor on PortA.0. Can I apply the following code from markedwards?

ADCIN 1,AD1 'read channel 1...AN1
AD1 = AD1 >> 6 'justify data

ADJUSTFAN: 
IF AD1 < 2 then FANSPEED = 153 '60% min speed
IF AD1 >= 3 then SPEED = 178 '70%
IF AD1 >= 5 then SPEED = 204 '80%
IF AD1 >= 7 then SPEED = 229 '90%
IF AD1 >= 9 then SPEED = 255 '100%
IF SPEED > SPD THEN SPD = SPD + 1 'accelerate
IF SPEED < SPD THEN SPD = SPD - 1 'de-accelerate
hpwm 2,SPD,32760 ' PWM 20,000 Hz

As I understand I need a pic that support HPWM, please forgive me if this may sound very basic but how I connect the assigned port pin to the motor?

I have tried using L298N, which I can stop, turn cwise and ccwise the motor, can I also control the speed and can anyone show simple code how to do this?

Thanks in advance,
joe

I am not sure about the logic of the code.
But a very easy way of having the control of a motor by analog pin (with a pot) should be like:

ADCIN 0, CCPR1L ' Read Pot, and put the result directly to PWM register. Assuming 8-bit adc reading.

Why don't you first try to see the result of this one line of code and then go on?

[joseph Degorio]

ADCIN 0, CCPR1L ' Read Pot, and put the result directly to PWM register. Assuming 8-bit adc reading

Hi sayzer, thanks for the time. I settle to use L298 because that's what I have right now. Can you help me check my connection between the PIC and L298..is this okay? Like I said in first post I was able to control the L298 but without PWM conttrol on PortB. Now I want to apply the PWM on PortC.1, but not really sure how is the connections...

thanks in advance,
joe

[sayzer]

Hi sayzer, thanks for the time. I settle to use L298 because that's what I have right now. Can you help me check my connection between the PIC and L298..is this okay? Like I said in first post I was able to control the L298 but without PWM conttrol on PortB. Now I want to apply the PWM on PortC.1, but not really sure how is the connections...

thanks in advance,
joe

I never used L298, I always made my own H-Bridge.
Using PWM on L298, some people drive Enable pin by PIC's PWM output. I am not sure how effective this is.
I would, however, use 7408 AND gate (two gates, one pin common to PWM pin), others to direction pins.
This way, you always have a PWM channel, and also have the control of the direction.

______________________

[joseph Degorio]

thanks, sayzer. I will try to take time to study it.

regards,
joe