Tough assembly program for the PIC16F84 - Page 3 - Electronic Circuits Projects Diagrams Free

JohnBrown · 2nd December 2004, 07:51 AM

OK, if you can't be bothered to answer my questions, then I wash my hands of the whole thing. You're on your own as far as I'm concerned.

asmpic · 2nd December 2004, 12:01 PM

Quote:

Originally Posted by JohnBrown

What form does the keypad take? Judging from your "code" it has a strobe connected to RB0, and two databits connected to RA0 and RA1. Am I right?
If so, what are the other RA pins connected to? You will probably need to ANDLW 0x03 at some point to isolate bits 0 and 1, otherwise, when you attempt to ADD the keycode into the stored code, it won't work as you expect.

I dont know the answer to this question, my professor has mentioned nothing of this. All I know is that RB0 indicates the value on the INT pin on the PIC – when a rising edge (transition from 0 to 1) occurs on this pin, an interrupt is signaled to the PIC. The input values for pins RA2,
RA1, and RA0. RA2 is high when the Enter key is pressed. RA1 and RA0 encode the four number keys into 2-bits. It is assumed that only a single key is pressed at a time. I dont know if that's the answer you're looking for but that's all I know about that.

Quote:

Originally Posted by JohnBrown

Do you actually have the hardware to test this on, or are you just programming into a black hole?

I'm using MPLAB and I don't have the actual PIC (PIC16F84) but a simulator of it.

Quote:

Originally Posted by JohnBrown

You've still not fixed your interrupt routine, which trashes the STATUS register. Also, you seem to have copied the faulty context saving into your grant_deny or whatever it's called.

Again, I cannot edit the interrupt routine nor the grant_deny. Those were all given by my professor. The only thing I'm allowed to touch are subroutines starting at "update_pass_code" which is what I have added to his code.

asmpic · 2nd December 2004, 04:28 PM

Sorry, double posted by mistake

asmpic · 2nd December 2004, 04:29 PM

I know exactly what needs to be done but I just can't program it in assembly. I'll show you guys the pseudo code for the compare_pass_code subroutine. I think my main problem is using FSR and INDF, I just don't seem to understand how to use those.

Code:

compare_pass_code

if supervisor_mode==1
     store passcode in list
     clear supervisor mode

else
      if entered_pass_code==0x1B (supervisors passcode)
            set supervisor_mode=1
       
       else
            compare entered_pass_code to list of authorized passcodes
            if match found
                add to list
                set success=1
                call grant_deny
            
           else
             no match found is found, set success=0
             call grand_deny

asmpic · 3rd December 2004, 06:50 PM

Can someone please give me some advice or help me out with converting the pseudo code I have to assembly language so I can finally get this program finished?

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2nd December 2004, 07:51 AM	(permalink)
JohnBrown	OK, if you can't be bothered to answer my questions, then I wash my hands of the whole thing. You're on your own as far as I'm concerned.

2nd December 2004, 04:28 PM	(permalink)
asmpic	Sorry, double posted by mistake

3rd December 2004, 06:50 PM	(permalink)
asmpic	Can someone please give me some advice or help me out with converting the pseudo code I have to assembly language so I can finally get this program finished?