HPWM confusion

[Melanie]

>> But I was wandering what the command ccp1 does in the Pic16f876a chip does.

CCP1 is NOT a command, but a REGISTER within your PIC.

To discover what it does, download and read the Datasheet for your PIC16F876A. A really good place to start is section 8 - Capture/Compare/PWM Modules.

[sayzer]

Welcome back Melanie!



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[lerameur]

So grossely, I am doing a line following robot, if I use PWM, then the sensors are not working. Also, I only have two channel to use PWM, so only two motors can use HPWM on one chip. right?

k

[mat janssen]

Thats wright.
A 16F87(3)6 should do it. It has 2 Hpwm outputs.

[lerameur]

HI,

I am using an H-bridge L293. It seems that there are thre wires per motor for control. 1 for neg. , 1 for pos. and one for the HPWM. The PWM is put on the CCP1, while the other do not matter, as long as they are configured as 1 or 0 right ? well thats what I concluded from what I read. Is there any reason why this code would not work ? I am not getting any output

if right > left Then
temp =right-left
temp= temp * 254
temp= temp/right
PORTC.4=0
PORTC.5=1
HPWM 1,255-temp,1000
HPWM 2,255,1000

Else
temp =left-right
temp= temp * 254
temp= temp/left
PORTC.4=1
PORTC.5=0
HPWM 2,255-temp,1000
HPWM 1,255,1000
Endif

[lerameur]

To be more precise, the circuit seems to wok without the motor connected. when i conencted the motor, then the LCD screens shows very low numbers, and the motor might turn just for 1-2 seconds, otherwise it makes a noise, I guess thats my 2000hz
Just one time the motor turned on and changes direction 3 times very quickly.

Should my power supply for the L293 be different then for the pic ?

k

[lerameur]

last code still not working
Again i hear a buzz, and sometime the motor turns a little.
Also on the oscilloscope, sometime he output is sitting at zero, or when its oscillating, it looks like its going from -4 to 1volt

if right > left Then
temp =right-left
temp= temp * 254
temp= temp/right
PORTC.4=0
PORTC.5=1
HPWM 1,255-temp,2000
HPWM 2,255,2000
Endif

if left >= right then
temp =left-right
temp= temp * 254
temp= temp/left
PORTC.6=0
PORTC.7=1
HPWM 2,255-temp,2000
HPWM 1,255,2000
Endif