Led + resistor ?

[skimask]

Maybe there is something in this pic's hardware to produce this behavior.

Solderless breadboard?
Move everything up/over a few holes and see what happens...

[ruijc]

Hello Skimask,

It's on the solderless breadboard that it's working as it should.

It's on the pcb that i get this strange behavior.

I'm beginning to suspect that the max1724 is not handling it very well.

i'm going to simulate on the breadboard the final circuit ( including the max1724 ) and let's see what happens .

[falingtrea]

You need to check the data sheet for the specific PIC device you are using. Not all pins are direct drive. Some are only open collector and need pull-ups if you need a high output. Also, what level are you using to turn your LEDs on? The I/O pins will drive a higher current for a low(8.5 mA) than a high(-3 mA). So the best bet is to connect the LEDs to you positive rail to the anode and the I/O pin to the cathode.

[ruijc]

Thanks falingtrea, that is a good idea.

In fact i was going to change my code to do that by i remembered that one of the ports i mentioned is one bi-color led ( green and red with comon anode ) and the green one doesn't light up.

This was what i changed :

PortA.7 and portB.4 added a 2K resistor in series.
Remaining ( working ) ports...left as is ( meaning...without resistors )

Result :

Now all led light up normally !!!

Still, i have to mention the hardware feature in these 2 ports that produce this behavior.

I searched the 16F88's datasheet and i could not find anything that could link to this .

.