h-bridge help

hello
i am just trying a simple circuit , and as usual its not working.

its just a simple h-bridge made from L298 , i gut it from
https://www.hobbyengineering.com/H1918.html

it works fine Alone

now i tried to attach it to a PIC controller.

i make RB0 hi on one of the pins that suppose to turn the motor in 1 direction.
but nothing happens , when i attach this pin to +5V the motor turn but when i attach it to the PIC RB0 pin it wont move

the h-bride motor voltage that i am suppling is 6V,1.5amp

now a have a few questions also that i dont understand

1. when i operate the h-bridge circuit alone (no PIC), i dont use the enable line. i just attach one of the direction pins and the motor just spins left of right, isnt the enable pin suppose to be hi in order for it to work ??


2. does the current supplied from the PIC is not enough to switch the h-bridge , and i still need to have a transistor ?


I will appricte your help so much

thanks

If the cct work fine with 5V input voltage, maybe the PIC output is open-drain type. Try connect 1k pull-up resistor.

i did

i already did that as i am using a devlopment board with build in programmer, still didnt work

..

i measured the voltage coming out from the PIC RB0 it is giving 4.81v
so i guess its working
but the h-bridge wont work at all !!

The Enable pin must be High, don't left floating.

.

i just noticed, that enable is hi by default , it doesnt need to be set to hi as it is always hi

The datasheet say: normal TTL inputs. I don't see any internal pull-up resistor in the internal cct. Just try it.

..

ok i just attached a 10k pull up resistor
nothing changed

Mistery... and still work without PIC?

..

yes i even tried it with 9v battary and it worked fine

Post Your complete sematic for consideration. Today no more idea, i go to sleep

If you look at the L298 datasheet you will see several interesting things:
- Vs (motor supply) needs to be at least 2.5V above logic supply. the logic supply is 5V so the min Vs should be 7.5V. I don't understand why they spec the board for 6V.
- The L298s saturation voltage (total drop) is really high: 3.2V at 1 amp. so with 6V in, your motor will see a touch less than 3V.

try a higher voltage.