Help with passcode

Hi all,

I'm currently trying to get a passcode working for a BCD input (i.e. DTMF decoder output)

I have the BCD Input as follows

GetDtmf:
dtmf = 0
IF DT0 = 1 Then 'Check Input port 0
dtmf = dtmf + 1
EndIF
IF DT1 = 1 Then 'Check Input port 1
dtmf = dtmf + 2
EndIF
IF DT2 = 1 Then 'Check Input port 2
dtmf = dtmf + 4
EndIF
IF DT3 = 1 Then 'Check Input port 3
dtmf = dtmf + 8
EndIF

So each BCD line is added to the VAR dtmf,

Then further down I have a lookup section of code

C = C + 1 'Add 1 to Tone Count Register
LookDown dtmf,["0,4,8,2,3,9,1,7,5,6"],J 'LookDown Table
IF J = 0 then error
IF C = 1 AND J = 1 Then Key 'Check Codes are sent in correct order
IF C = 2 AND J = 2 Then Key
IF C = 3 AND J = 3 Then Key
IF C = 4 AND J = 4 Then Key
IF C = 5 AND J = 5 Then Key
IF C = 6 AND J = 6 Then Key
IF C = 7 AND J = 7 Then Key
IF C = 8 AND J = 8 Then Key
IF C = 9 AND J = 9 Then Key

So if I send a 4 on DTMF which will activate DT2 and write 4 to the var dtmf, then the loookup table should see the 4 at position 1 and write a 1 to the var J, problem is it's error out here at the line
IF J = 0 then error ..

Any ideas anyone please?

Regards,

Jim

Jim, Here is how I do it for a repeater control link w an 16F628.

CHECKIN:' GATHER TOUCH TONE DATA FROM RECEIVER
DVEDGE = 1 'REMEMBER THE LEADING EDGE
POINTER = PORTA & 15 'PULL IN DATA AND STRIP TO 4 BITS

REORDER:' REORDER OUTPUT FROM TONE DECODER
' ACTUAL KEY= D 1 2 3 4 5 6 7 8 9 0 * # A B C
lOOKUP POINTER,[$D,$1,$2,$3,$4,$5,$6,$7,$8,$9,$0,$E,$F,$A,$B,$C],POINTER
IF POINTER = $F THEN EVALKEY 'IF # KEY THEN EVALUATE TONE SEQUENCE
CCOUNT = CCOUNT + 1 'ADD 1 TO THE CODE COUNTER
CCOUNT = CCOUNT MIN 9 'LIMIT TOUCH TONE CHARACTERS
TONES(CCOUNT) = POINTER 'COPY TONE TO ARRAY FOR LATER EVALUATION
GOTO LOOP

EVALKEY:' EVALUATE TONE SEQUENCE
TONE = 0 'CLEAR TONE OUTPUT FLAG
BADCOD = 1 'SET BADCOD FLAG
IF CCOUNT > 6 THEN
FOR SCRATCH1 = 1 TO 4
CODEWRD = CODEWRD << 4 'MAKE ROOM FOR THE NEW CODE
CODEWRD = CODEWRD | TONES(SCRATCH1)
NEXT
IF CODEWRD = UNLOCK THEN 'IF CORRECT UNLOCK CODE THEN EVALUATE REST OF MESSSAGE
CODEWRD = 0 'MAKE ROOM FOR THE NEW CODES
ENDIF

Hi Dave,

Thanks for the info, I'm struggling to understand what's happening in your code.

This is also for a repeater, I'm trying to program 3 different modes, the first being basic users so no access code is required, this works fine, next I want an advanced user section which is only active after a pass code is entered and finally the keepers section which is only active after another different passcode.

So i have the system working except for the 2 passcode areas which i'm using the lookdown which doesn't seem to be working and i'm, not sure why.

If I save a value .. lets say 1 into a var named code

then I use the following line

LookDown code,["0,8,1,4,2,9,3"],J

Surely the var J should then have the value of 2

Am I correct?
If so this is not happening and I dont know why.

I'm unclear as to how your system is looking for a passcode.

Regards,

Jim

Jim, Tones(*) is an array for storing the incomming touch tones. The first 4 tones are the password. The tone is decoded into a nibble of either 0,1,2,3,4,5,6,7,8,9,a,b,c,d,e,f. These are shifted into a word sized variable called codewrd. After all 4 tones are shifted into codewrd it is compared to a constant called unlock. It once again can have a value of 0000 to ffff. If the two compare then the system is unlocked...... This same type of method can be used for even longer unlock codes.

Dave Purola,

Hi Dave,

OK I'll look a little more in depth at the code.

For now I have scrapped the lookdown table and i've gone with a simple code as follows:-

IF dtmf = 4 Then 'First code digit
gosub Getdtmf
else
goto error
ENDIF
IF dtmf = 1 Then 'Second code digit
gosub Getdtmf
else
goto error
ENDIF
IF dtmf = 7 Then 'Third code digit
gosub Getdtmf
else
goto error

This seems to work OK, but I have no option of changing the code remotely.

How could I store the codes and re-program them remotely from the DTMF decoder?

Regards,

Jim