L298N Motor Driver using pwm code not working..

[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

[tacbanon]

Hi, I did manage to add the other motor, right now I made as a line tracker robot . Not very well on the curves yet and a little slow..hope you can look onto my codes and might able to improve the performance..

DEFINE osc 4         
ANSEL = %00000111 ' Make AN0-AN7 Analog
ANSELH= %00000000 ' Make AN8-AN13 digital

TRISA  = %00111111
ADCON1 = %00001001 
TRISC = 0
TRISD = 0
TRISB = 0

;-------------Variables
senCenter var byte
senRight  var byte
senLeft   var byte 

i var word
i = 0
PORTD.0 = 1 ' In1 
PORTD.1 = 0 ' In2
PORTB.0 = 1 ' In3 
PORTB.1 = 0 ' In4

; PORTC.4 PWM Signal  

loop1:
   Adcin 0, senCenter
   Adcin 1, senRight
   Adcin 2, senLeft
   ;Serout2 PORTD.2, 84, [$1B,$45,Dec senCenter," ", DEc senRight," ",Dec senLeft]
   ;------------------------Select options seen by the sensors
   IF senCenter > 150 and senRight > 150  then 
       Gosub movExtRight
    Endif
   
   IF senCenter > 150 and senLeft > 150  then 
       Gosub movExtLeft
    Endif
   
    IF senCenter > 150 then 
       ;Serout2 PORTD.2, 84, [$1B,$45]       
       ;Serout2 PORTD.2, 84, [$D,"     Center"]
       gosub movForward
    Endif
    IF senRight > 150 then        
       ;Serout2 PORTD.2, 84, [$1B,$45]
       ;Serout2 PORTD.2, 84, [$D,"Rigth"]
       gosub movRight
    Endif
    IF senLeft > 150 then        
       ;Serout2 PORTD.2, 84, [$1B,$45] 
       ;Serout2 PORTD.2, 84, [$D,"           Left"]
       gosub movLeft
    Endif
   ;------------------------
   
   ;gosub movForward

 
GOTO loop1               ' Do it forever

    END

movForward: '  forward
PORTD.0 = 1 ' In1 
PORTD.1 = 0 ' In2
PORTB.0 = 1 ' In3 
PORTB.1 = 0 ' In4
PWM PORTC.4 ,200,10 
PWM PORTC.5 ,200,10
return

movExtRight: ' turn more to the right
PWM PORTC.4 ,50,10 
PWM PORTC.5 ,200,10
return

movRight: '  short right
PWM PORTC.4 ,100,10 
PWM PORTC.5 ,200,10
return

movLeft: '   short left
PWM PORTC.4 ,200,10 
PWM PORTC.5 ,100,10
return

movExtLeft: ' turn more to the left
PWM PORTC.4 ,200,10 
PWM PORTC.5 ,50,10
return

senLost: ' Getback no line detected
PORTD.0 = 0 ' In1 
PORTD.1 = 1 ' In2
PORTB.0 = 0 ' In3 
PORTB.1 = 1 ' In4
PWM PORTC.4 ,200,5 
PWM PORTC.5 ,200,5
pause 50
return

Thanks in advance,
tacbanon

[HenrikOlsson]

Since you're using the 16F887 which has two CCP-modules the first thing I'd do is the rewire the thing so that the EN-pins of the L298N are connected to PortC.1 and PortC.2 and use HPWM instead.
That way the PWM generation is handled in the background, by the CCP-modules (instead of tying up the processor) and you only need to update it when you want to change the speed. Your program gets a lot of time to do other things.

Then I'd probably set up a timer interrupt to trip every 25ms or something. In the ISR I'd read the sensors and set the PWM dutycycles accordingly.

[tacbanon]

Hi, I'm back...I got the HPWM working and also the timer. But I can never make the robot stay on track/line . Probably my setup is not right or something...kindly check my codes, hoping you can help me out spot what I'm doing wrong.

DEFINE OSC 4  
         
ANSEL = %00000000 ' Make AN0-AN7 Digital
ANSELH= %00000000 ' Make AN8-AN13 digital
;--------- Setup Interrupt-------------------------- 
INCLUDE "DT_INTS-14.bas"     ' Base Interrupt System
INCLUDE "ReEnterPBP.bas"     ' Include if using PBP interrupts

ASM
INT_LIST  macro    ; IntSource,        Label,  Type, ResetFlag?
        INT_Handler   TMR1_INT,  _CheckSensors,   PBP,  yes
    endm
    INT_CREATE               ; Creates the interrupt processor
ENDASM
;--------------------------------------------------
T1CON = %00100001                ; 00110001  Prescaler = 8, TMR1ON
@ INT_ENABLE  TMR1_INT     ; enable Timer 1 interrupts

;--Setting HPWM
TRISC.1 = 0 'Set CPP2 to PWM output
TRISC.2 = 0 'Set CPP1 to PWM output
CCP1CON = %0001100 ' Set CCP1 to PWM, Active High
CCP2CON = %0001100 ' Set CCP1 to PWM, Active High

TRISA  = %00111111 ' did not anymore use this for now
ADCON1 = %00001001 
TRISC = 0
TRISD = 0
TRISB = %10000111 ' 0-2 for sensors
PortB = %00000000 ' Reset PortB
OPTION_REG = $7f
;--Init variables
i var Byte
i = 0 ; 200
;-- wheel on forward
PORTD.0 = 1 ' In1 
PORTD.1 = 0 ' In2
PORTD.2 = 1 ' In3 
PORTD.3 = 0 ' In4
;-------------------Speed of motor--
Gear var byte[10]

;--Set allowable speed---
Gear[1] = 0 
Gear[2] = 75 ' start slow roll
Gear[3] = 80

pause 2000
i = 2

MainLoop:  
 ;pause 100 
 
; Start rolling
HPWM 1 ,Gear[i],10
HPWM 2 ,Gear[i],10

GOTO Mainloop               ' Do it forever

END

'---[TMR1 - interrupt handler]--------------------------------------------------
CheckSensors:

if PortB.0 = 1 and PortB.2 = 0 then ' Left sensor
   HPWM 1 ,Gear[3],10
   HPWM 2 ,Gear[2],10
   pause 20          
   ;Serout2 PORTB.6, 84, [$D,"Right           "]
ELSE
if PortB.1 = 1 and PortB.2 = 0 then ' Right sensor
   
   HPWM 1 ,Gear[2],10
   HPWM 2 ,Gear[3],10  
   ;Serout2 PORTB.6, 84, [$D,"            Left"]
   pause 20
ELSE
if PortB.2 = 1 and PortB.0 = 0 and PortB.1 = 0  then  ' Center sensor
   i = i + 1
   if i > 2 then
   i = 3
   ENdif
   ;Serout2 PORTB.6, 84, [$D,"    Center      "]
ELSE
;-------------------More than 1 sensors detected
if PortB.0 = 1 and PortB.2 = 1 then ' Left and Center sensor
   
   HPWM 1 ,Gear[3],10
   HPWM 2 ,Gear[3],10 
   ;Serout2 PORTB.6, 84, [$D,"Right-Center    "]
Else
if PortB.1 = 1 and PortB.2 = 1 then ' Right and Center sensor    
   
   HPWM 1 ,Gear[3],10
   HPWM 2 ,Gear[3],10  
   Serout2 PORTB.6, 84, [$D,"Center-Left     "]
Else
if PortB.0 = 0 and PortB.2 = 0 and PortB.1 = 0 then ' Can't see no line
   ;HPWM 1 ,Gear[0],10
   ;HPWM 2 ,Gear[1],10 
   Serout2 PORTB.6, 84, [$D,"No more line?   "]
   pause 50
ELSE
   Serout2 PORTB.6, 84, [$D,"Error???         "]  ' Others
ENdif:ENDIF:ENDIF:ENDIF:ENDIF:ENDIF 
  
@ INT_RETURN

Thank you in advance,
tacbanon

[HenrikOlsson]

Hi,
I don't really follow your coding but you have a main loop which constantly (I mean thousands of times per second) keeps setting the dutycycle to some value. When the interrupt fires, decide which way to turn (if any) and set the dutycycle, don't change it the main loop. BTW, does 10Hz really work? Also, in your previous code I got the impression that the sensors were analog (you used ADCIN to read them) but now they are digital?

/Henrik.

EDIT: One more thing, you don't seem to reload the timer value in the ISR.
Since the timer is freerunning and generating an interrupt on overflow, with a prescaler of 8 and a 4MHz x-tal the interrupt frequency of 4000000/4/8/65536=1.9Hz, I think you need to run faster than that.

[tacbanon]

Hi Henrik, thanks you for your comments..I guess I have to rearrange my codes.

don't change it the main loop.

Does this mean I have to remove this in the main loop..

; Start rolling
HPWM 1 ,Gear[i],10
HPWM 2 ,Gear[i],10

and place it in a sub program?

I did remove the analog reading to digital because I thought it will better...don't you think so?

Regarding the timer, should this be the value T1CON = %00100001 ?
I really appreciate for answering my questions..not really all clear to me at this time but I hope I will learn some if not all.
BTW do you think it is best to have a fix speed instead of changing from time to time?

regards,
tacbanon

[HenrikOlsson]

Hi,
HPWM works in the background, once you tell it to output a certain dutycycle with a certain frequency it does that in hardware. There's no need to continously execute the HPWM commands like your doing in your main loop.

If you change the prescaler to 1:1 you'll get an interrupt every 65536us or around 15Hz, I'd try that as a starting point. If you need faster interrupt rate than that you need to preload the TMR1 register in the ISR so that it doesn't start from 0. If you load with 55536 there will be 10000 cycles (or 10000us in this case) untill the next interrupt.

I have no idea if analog or digital sensor is best. I don't even know what sensors you're using....

If you have two sensors, one on "each side" of the line then I think two speeds for each motor should do. Run both motor at the lower speed to go straight forward, increase the speed of one motor to turn. (Or do the oposite if you want).