Problem with PIC16f72

[chris92]

I really appreciate everyone here trying to help. I think am really very far behind in electronics. If u have help on basic electronics, i 'd appreciate. Thanks a lot

 

[chris92]

Nigel in main board schematic, you did not include the MCLR!

 

[Nigel Goodwin]

So I either use the resistor or transistors.

No, you MUST use the resistors regardless, you only need the transistors if you're switching the entire 7 segment display and wanting to run at higher currents than the PIC can support.

My 8x8 LED matrix tutorial board uses no transistors (in order to keep it simple) and survives quite happily - but for the tutorials we're not looking for 'super' brightness or anything.

 

[Nigel Goodwin]

Nigel in main board schematic, you did not include the MCLR!

On the 16F628 you can set it to be internal - this allows you full use of 16 I/O pins - with some limitations. This was one of the reasons for using the 16F628.

 

[Ian Rogers]

You can test it.... Put your micro on a piece of breadboard with all portb pins toggling at about 2hz.... Then connect an LED to each pin in turn ( using a 270-330 ohm resistor)..

 

[Nigel Goodwin]

Please any idea of a software that can help me make schematics like the ones in

I use SPlan

 

[3v0]

So I either use the resistor or transistors.

The resistor used with the LED is to limit the current. If you use a transistor you will still use a resistor on its base to limit current to the transistor.

If you intend to lay out PCBs in the future learn to use eagle. It allows you to create the schematic. Then when you layout the PCB the software uses your schematic to help you create the artwork. It shows you what pins need to be connected with airwires or rubber bands, both are just another way of saying lines. It saves a lot of time.

Your first concern is still determining if the PIC is running code.