Good day to all! Can somebody help me in programming a 3 digit 7 segment up and down counter? The count is from 0 - 999. Input/switch is RA3 and RA4. Ouputs are RB6 -G, RB5 - F, RB4 - E, RB3 - D, RB2 - C, RB1 - B and RB0 - A.

 

I almost forgot, I'm using .ASM language.

 

Then you also will need to use RA0, RA1, and RA2 to select which digit you are currently displaying. You should use the output to drive a transistor or MOSFET to supply or sink enough current to/from the common terminal.

 

yeah. i'm using RA0 for the first digit, RA1 for the 2nd and lastly RA2 for the 3rd digit.

 

i'm using common anode 7 segment display and an npn 2n9006 transistor.

 

I believe you mean 2N3906 instead of 2N9006.
That should work as long as your LED display's power supply is the same as your PIC's power supply. The 2N3906 is pretty much limited to sourcing about 100mA.

Maybe someone will be able to help you with the Asm portion. I'm really tied up today.

 

This should give you a general idea, the second post has the simpler version of the code. It's not for the same chip, and it's a voltmeter, not a counter, but it's got all the multiplexing and binary to BCD and 7-segment code that you need.
http://forum.allaboutcircuits.com/showpost.php?p=342284&postcount=797
http://forum.allaboutcircuits.com/showpost.php?p=362409&postcount=27

 

Thank you for the response Sir. But I still don't get it.

 

I almost forgot, I'm using .ASM language.

I might have source code around from years ago.
2-digit LED display, 16f54, assembler.

How much will you pay for this? But this is only a joke.

Have you done any work yet? Like soldering the circuit, or building it on breadboard? Have you written any code? Did you set up a PIC programmer? MPLAB maybe?

 

May be you can start with a 2 digits 7-segment counter. Here is the link

Hardware

http://www.winpicprog.co.uk/pic_tutorial_7seg_board.htm

Software

http://www.winpicprog.co.uk/pic_tutorial10.htm

Though it was written for 16F628A, it can easily be modified to run on 16F84A. There are 3 controller boards in the Hardware section.

Instead of using RA0-2, it just need one Ra port pin to control digit 1 & 2.

Allen