Need help in program for remote control using PIC16F84A

[Madscientist]

Hello all,

I am new to PIC programming and am using a PIC16F84A. I would like to program it to make one of the pins go "high" when, and only when the input pins accept a certain binary code and in a particular order. Example:

Pin 6 is low, pin 7 is high, pin 8 is low and pin 9 is low. That would be the binary code "0100" or simply the binary code for the number "4"

The next inputs would be:
Pin 6 is high, pin 7 is low, pin 8 is low and pin 9 is high. That would be the binary code "1001" or simply the binary code for the number "9"

And finally:
Pin 6 is low, pin 7 is low, pin 8 is high and pin 9 is low. That would be the binary code "0010" or simply the binary code for the number "2"

After that sequence has been completed, I want to have the output of another pin go "high"

The binary codes that are inputed into the PIC are generated from the output of a DTMF decoder. In other words, I want to press "492" on a touch tone keypad and have it activate a project. Basically I want to control a project remotely from a telephone.

Any help on the source code would be appreciated. Like I said, I am very new to programming but enjoy designing electronic circuits.

Darren

[mister_e]

help us a little bit and provide your DTMF decoder chip model.

[Madscientist]

I use the 8870 chip. It is an 18 pin DIP. Its input is DTMF from a phone or receiving radio. The output is a binary code ( four pins ). The only place I have seen this decoder is at BG micro.com out of Texas. I have used several of them and they always work perfect. I want to run the four output pins of the 8870 to four inputs on the PIC MCU 16F84a. The 8870 DTMF decoder holds the output constant until a new tone is entered in. In other words, if I touch the number 3 key on a touch tone phone, the output on the 8870 would be "0011" until I touched another key.

Furthermore, I am using an epic programmer from ME lab and the PicBasic compiler (if that helps). And let me remind you, I'm an idiot when it comes to programming these things. I'm just getting started. Thanks for the reply. Any help would be appreciated.

Darren

[mister_e]

Sounds simple to me. Any schematic could be handy to start.

[Madscientist]

I put together a schematic of the project I am designing. Sorry that it is a little "scrunched" but I assume you don't have the software that I am using to design it. It was difficult to get the entire schematic on the screen at one time. I designed it on Livewire by New Wave Concepts. I converted the image to a JPEG photo and am sending it as an attachment for your ease of viewing. Thanks again for your input. ( let's see if I am actually successful in attaching the photo, hahahaha)

Darren

[mister_e]

the most inefficient way but easy to follow.

LOW PORTB.4
Key var byte

start:
    Key=(PORTB&$0F) rev 4
    If Key<>4 then Start
    While key 
        Key=PORTB&$0F 
        wend 
    pause 50

    Wait2nd: 
        Key=(PORTB&$0F) rev 4
        if key=0 then Wait2nd
        If Key<>9 then Start
        While key 
            Key=PORTB&$0F 
            wend 
        pause 50

    Wait3rd:
        Key=(PORTB&$0F) rev 4
        if key=0 then Wait3rd
        If Key<>2 then Start
    
    HIGH PORTB.4    
Spin:
    goto spin