L298N Motor Driver using pwm code not working..

[tacbanon]

Hi, I know I have unfinished topic in another thread, but I'm still waiting some parts to come, so I decided to move on to my simple mobile robot structure. The sensors mentioned from the other thread are going to be placed on this three wheeled robot. But I hit another brick wall. I've been losing my head since this morning..it's 2Am now already . I hope anybody can help me out..I'm having trouble driving the motors using PWM. When not using the PWM, motors work great...please see image\schematic below.

Attachment 6682
My setup
Attachment 6684
My codes:

Define OSC 20
ANSEL=%00000000
ANSELH=%00000000
TRISC = 0
PORTC = 0
TRISD = 0
PORTD = 0

MainLoop:
PortD.0 =1
PortD.1 =0
PortD.2 =1
PortD.3= 0
PortC.4 ,127, 100
PortC.5 ,127, 100

Goto MainLoop

Can any one spot what I'm doing wrong...I appreciate any input.

Kind regards,
tacbanon

[HenrikOlsson]

That code looks just wrong.
You set four outputs on PortD while the schematic shows PortC.
Then you seems to missing the actual PWM statement, and if you meant to PWM the Enable pins you have those too on the wrong pins.

I'm surprised if that code even compiles.

/Henrik.

[tacbanon]

Hi Henrik,
My bad, uploaded the wrong image(must be very tired last night)
[ATTACH=CONFIG]6686[/ATTACH
Thanks for the replying...I will try it today and post here my output.

and if you meant to PWM the Enable pins you have those too on the wrong pins.

..aren't pin5 and pin6 the PWM pins on JP6?


/tacbanon

[tacbanon]

Hi, kindly check if this should be the right pins assignment.
PortD.0 to input3 of l298
PortD.1 to input4 of l28
PortC.0 to enable of l298

by henrik: I'm surprised if that code even compiles.

Really sorry..next time I will double check before uploading.
Code:
PWM PORTD.0, 127,100
PWM PORTD.1, 127,100
PortC.0 = 1

Hope I'm close...

/tacbanon

[HenrikOlsson]

Concentrate on one bridge and motor to begin with, when you have that working apply the same procedure to the second bridge/motor.

Bridge 1 is controlled In1, In2 and ENA - in your case (according to your latest schematic) PortD.0, PortD.1 and PortC.4 respectively.
To drive the motor forward you drive PortD.0 high, PortD.1 low and apply the PWM signal to PortC.4

PortD.0 = 1
PortD.1 = 0

Main:
For i = 0 to 200              ' Ramp up.
   PWM PortC.4, i, 10
NEXT

For i = 200 to 0 Step -1  ' Ramp down.
   PWM PortC.4, i, 10
NEXT

Pause 500

Goto Main

According to the photo of the board there are a jumper for each bridge which says Remove jumper for PWM - did you do that? If you didn't the EN-pins are tied high and will short your PWM signal to the boards Vcc.

/Henrik.

[tacbanon]

Thank you Henrik for saving me hours of time just to make it ...I got it finally! I will try to add the other bridge, then post here my result.

regards,
tacbanon