Help with serin, serout, Manchester encoding

[oneohthree]

I am trying to transmit 4 bits from a TLP-315 transmitter to a RLP-315 receiver for a project. At the receiver, I am taking the four bits and performing some comparisons on it and getting an output. I am using two PIC16F88 microcontrollers. I was wondering whether I coded the Manchester coding and used the serin, serout correct. Also, since I am using Manchester coding, do I have to send a preamble? I have attached my code below.

'Transmit
Include "Modedefs.bas"
v var word 'v is a byte to be encoded
counter var byte 'counter is a byte
encoded var word 'encoded is a word sized variable that holds the encoded byte v
'Code to be transmitted
v = 1010
'Manchester Encoding
For counter = 0 to 3 'number of bits to be encoded (4 bits)
If v.0[counter]=0 Then
encoded.0[counter*2]=0
encoded.0[counter*2+1]=1
Else
encoded.0[counter*2]=1
encoded.0[counter*2+1]=0
EndIf
Next counter
'Serial Out
serout PORTB.0, n2400, [encoded]


'Receive

'Include "Modedefs.bas"
s var word 's is a byte to be encoded
B0 var byte 'B0 is a byte
B1 var byte 'B1 is a byte
'counter var byte
encoded1 var word 'encoded1 word sized variable that holds the encoded byte v
action var byte 'action variable
alert var byte 'alert variable
B0=0 'hardwired address
B1=1 'hardwired address

'Decoding
loop:
serin PORTB.0, n2400, [encoded1]
For counter = 0 to 3
s.0[counter]=encoded1.0[counter*2]
Next counter
goto loop
End

'Tracking code
If (s.2==0) & (s.3==0) Then 'If the code matches 00 then it is in the tracking mode

If (s.0==B0) & (s.1==B1) Then 'If the address matches then
s.2=1 'Change the third bit to 1
action = s.2
alert = 0
serout PORTB.1, n2400, [s] 'Send the changed word back
Else
s.2=0 'Since the addresses does not match do not change anything
action = s.2
alert = 0
serout PORTB.1, n2400, [s] 'Send the changed word back
Endif
Endif

'Tracking and Finding code
If (s.2==0) & (s.3==1) Then 'If the code matches 01 then it is in the tracking and finding mode

If (s.0==B0) & (s.1==B1) Then 'If the address matches then
s.2=1 'Change the third bit to 1
action=s.2
alert=1
serout PORTB.1, n2400, [s] 'Send the changed word back
High 2
Else
s.2=0 'Since the address does not match do not change anything
action=s.2
alert=0
serout PORTB.1, n2400, [s] 'Send te changed word back
Endif
Endif

[skimask]

v = 1010

For one thing, sending 1010 isn't going to work. 1010 is one thousand and ten, not 10 or $A). You probably want v = %1010.

[oneohthree]

Also, I tested my transmitter and receiver with the microcontrollers. I was able to transmit the 1101 sequence from the transmitter to the receiver. I got the encoded version of the 1101 sequence. But, the microcontroller on the receiver end the serin command does not work for the microcontroller. When I look at the pins where I have serout on I don't see any signal. Did I do something incorrect?

[skimask]

But, the microcontroller on the receiver end the serin command does not work for the microcontroller.

What? Doesn't make any sense...

[oneohthree]

I don't know what is wrong either. Somehow the serin command isnt taking the data that I send in from the receiver. I check the output at pin 1 and pin 3 using a logic analyzer and I get nothing. Is there something wrong with my receiver code. Also, should I send data in inverted (n2400) or non-inverted (t2400)?

[skimask]

I don't know what is wrong either. Somehow the serin command isnt taking the data that I send in from the receiver. I check the output at pin 1 and pin 3 using a logic analyzer and I get nothing. Is there something wrong with my receiver code. Also, should I send data in inverted (n2400) or non-inverted (t2400)?

No, I meant your sentence didn't make any sense...

[oneohthree]

Do you have any suggestion on how I can get my serin command to work correctly?

[skimask]

Do you have any suggestion on how I can get my serin command to work correctly?

Yes, READ the WHOLE 'Serin SerOut Problem' thread, not to mention a half a dozen other PIC-PIC communication threads in the 'Serial' section of the forum, just like I've suggested in the other thread and more than once. And start simple and build up. You're still using the RF modules, but I don't see anything that says you're sure it all works without the RF modules. I don't see anything that says you're sure the whole thing works just between the 2 PIC's, a couple of buttons and a couple of LEDs.

[BrianT]

Simple RF receivers need a preamble to condition the data slicer. I have had great success with low power Rf comms by using a pseudo Manchester strategy.

Manchester code is usually recommended because it guarantees at least one transition per bit so a long run of 000 or 111 can be successfully decoded.

The following also works. Assuming a 4 bit nibble is to be sent, build a character of start bit, 8 data bits and one or preferably 2 or more stop bits. Use Char_Pacing to get extra stop bits. 8 bit bytes need to be broken into two halves before sending. A checksum on any data block is highly recommended.

Byte bit 0 is nibble bit 0
Byte bit 1 is inverted nibble bit 0
Byte bit 2 is nibble bit 1
Byte bit 3 is inverted nibble bit 1
Byte bit 4 is nibble bit2
Byte bit 5 is inverted nibble bit 2
Byte bit 6 is nibble bit 3
Byte bit 7 is inverted nibble bit 3

Now transmit this character many times - say 32 or more. The first few characters act as the preamble and the data stream is very nearly 50:50 duty cycle so the receiver data slicer is happy. Depending on link characteristics you may be able to cut the transmitted data down to 16 or even less repetitions.

Perform tests on the received character stream to make sure you receive it, say, at least 3 consecutive times, where the characters are identical to each other AND the data structure of bit/inverted-bit is obeyed. Activating parity can also give you an extra check.

I have used this with expensive 154 MHz transceivers and cheap 315 and 433 MHz Tx/Rx modules with great success.

HTH
Brian

[skimask]

The following also works. Assuming a 4 bit nibble is to be sent, build a character of start bit, 8 data bits and one or preferably 2 or more stop bits. Use Char_Pacing to get extra stop bits.
Brian

I agree with your strategy almost 100% ('cept I use lookup/lookdown tables).
But about the Char_Pacing above...
If the Char_Pacing value is too large (over a few of ms, 5ms for the TX/RX modules I use according to the spec's), the data slicer will lose it's mind and basically every byte will need a preamble.

[BrianT]

You are correct that setting Char_Pacing too long will defeat the purpose. The reason for adding an extra one or two stop bits is to prevent the problem where the SERIN software UART can misframe on a repetitive pattern and what it takes for the start bit may well be bit 3, 4, 5, etc. By giving the system 2 or 3 stop bits the SERIN command will fall into sync in just a couple of characters.

HTH
Brian

[skimask]

You are correct that setting Char_Pacing too long will defeat the purpose. The reason for adding an extra one or two stop bits is to prevent the problem where the SERIN software UART can misframe on a repetitive pattern and what it takes for the start bit may well be bit 3, 4, 5, etc. By giving the system 2 or 3 stop bits the SERIN command will fall into sync in just a couple of characters.

HTH
Brian

Good call, never really thought of that. I'm going to add that to a couple of my RF projects and see what happens. As it is, at 9600, I'm losing a few bytes here and there at the longer ranges. Maybe the 'extra stop bit' will help out.

[oneohthree]

I got serin to partially work on the receiver side (with and without wireless). The problem I am having now is it seems like after I decode it I have about 4 extra bits at the end of my decoded sequence. How do I get rid of it?

[skimask]

I got serin to partially work on the receiver side (with and without wireless). The problem I am having now is it seems like after I decode it I have about 4 extra bits at the end of my decoded sequence. How do I get rid of it?

And we're supposed to be able to help you fix that because we can see what your code looks like, right?

[oneohthree]

Here is my revised code:

------------------------------------------------------------------------------------------------------------------
'Transmitter Code
Include "Modedefs.bas"
v var word 'v is a byte to be encoded
counter var byte 'counter is a byte
encoded var word 'encoded is a word sized variable that holds the encoded byte v
'Code to be transmitted
v = %1101 '1101 in Binary
'Manchester Encoding
For counter = 0 to 3 'number of bits to be encoded (4 bits)
If v.0[counter]=0 Then encoded.0[counter*2]=0 'if it is a zero make the first bit 0 encoded.0[counter*2+1]=1 'make the second bit 1
Else
encoded.0[counter*2]=1 'if it is a 1 make the first bit 1
encoded.0[counter*2+1]=0 'make the second bit 0
EndIf
Next counter
'Serial Out
serout PORTB.0, t2400, [$55,$55, $55, $aa, encoded] 'serial out in pin 0 using non-inverted 2400 bps to encoded
--------------------------------------------------------------------------------------------------------------------------------
'Receiver Code
Include "Modedefs.bas"
s var word 's is a byte to be encoded
B0 var byte 'B0 is a byte
B1 var byte 'B1 is a byte
counter var byte
encoded1 var word 'encoded1 word sized variable that holds the encoded byte v
action var byte 'action variable
alert var byte 'alert variable
B0=1 'hardwired address
B1=1 'hardwired address

'Decoding
waitfor55:
serin PORTB.0, t2400, encoded1: if encoded1 = $55 then goto waitfor55
waitforaa:
serin PORTB.0, t2400, encoded1: if encoded1 = $aa then goto waitforaa

serin PORTB.0, t2400, encoded1 'serial in to pin 0, a non-inverting 2400 bps to encoded1
serout PORTB.3, t2400, [encoded1]
loop:
For counter = 0 to 3
s.0[counter]=encoded1.0[counter*2] 'proceed through counter and copy encoded1 to s
Next counter
goto loop
End
serout PORTB.3, t2400, [s] 'serial out to pin 3, a non-inverting 2400 bps, to s

'Tracking code
If (s.2==0) & (s.3==0) Then 'If the code matches 00 then it is in the tracking mode

If (s.0==B0) & (s.1==B1) Then 'If the address matches then
s.2=1 'Change the third bit to 1
action = s.2 'action becomes 1
alert = 0 'alert becomes 0
serout PORTB.1, t2400, [s] 'Send the changed word back, serial out to pin 1, a non-inverting 2400 bps, to s
Else
s.2=0 'Since the addresses does not match do not change anything
action = s.2 'action becomes 0
alert = 0 'alert becomes 0
serout PORTB.1, t2400, [s] 'Send the changed word back, serial out to pin 1, a non-inverting 2400 bps, to s
Endif
Endif

'Tracking and Finding code
If (s.2==0) & (s.3==1) Then 'If the code matches 01 then it is in the tracking and finding mode

If (s.0==B0) & (s.1==B1) Then 'If the address matches then
s.2=1 'Change the third bit to 1
action=s.2 'action becomes 1
alert=1 'alert becomes 1
serout PORTB.1, t2400, [s] 'Send the changed word back, serial out to pin 1, a non-inverting 2400 bps, to s
High 2
Else
s.2=0 'Since the address does not match do not change anything
action=s.2 ;action becomes 0 and alert is also 0
alert=0
serout PORTB.1, t2400, [s] 'Send te changed word back, serial out to pin 1, a non-inverting 2400 bps, to s
Endif
Endif

[skimask]

[QUOTE=oneohthree;35632]Here is my revised code:

That code is entirely TOO complicated for the job you are trying to get done...
Hang tight for a bit...

[skimask]

'Transmitter Code
Include "Modedefs.bas"
v var byte : counter var byte : encoded var byte : v = %1101
main:
For counter = 0 to 3
If v.0[counter]=0 Then
encoded.0[counter*2]=0
Else
encoded.0[counter*2]=1 : encoded.0[counter*2+1]=0
EndIf
Next counter : serout PORTB.0, t2400, [ $55 , $55 , $55 , $aa , encoded ]
goto main



'Receiver Code
Include "Modedefs.bas"
s var byte : B0 var byte : B1 var byte : counter var byte : cnt55 var byte
encoded1 var byte : action var byte : alert var byte : B0=1 : B1=1

main:
cnt55 = 0

waitfor55:
serin PORTB.0, t2400, encoded1

if encoded1 = $55 then
cnt55 = cnt55 + 1 'got $55, inc cnt55 by 1
if cnt55 = 3 then goto waitforaa 'if we got 3 in a row check for $aa
else
goto main 'if not $55, reset counter at main and restart
endif
goto waitfor55

waitforaa:
serin PORTB.0, t2400, encoded1
if encoded1 <> $aa then goto main 'restart, didn't get right leader

serin PORTB.0, t2400, encoded1 : serout PORTB.3, t2400, [encoded1]

For counter=0 to 3:s.0[counter]=encoded1.0[counter*2]:Next counter
serout PORTB.3, t2400, [s]

'Tracking code
If (s.2==0) & (s.3==0) Then
If (s.0==B0) & (s.1==B1) Then
s.2=1:action = s.2:alert = 0:serout PORTB.1, t2400, [s]
Else
s.2=0:action = s.2:alert = 0:serout PORTB.1, t2400, [s]
Endif
Endif

'Tracking and Finding code
If (s.2==0) & (s.3==1) Then
If (s.0==B0) & (s.1==B1) Then 'If the address matches then
s.2=1:action=s.2:alert=1:serout PORTB.1, t2400, [s]:High 2
Else
s.2=0:action=s.2:alert=0:serout PORTB.1, t2400, [s]
Endif
Endif

Your logic for getting the leader bytes and stuff was messed up, so I rewrote it a bit.

But I still think this is entirely too convoluted.
What exactly are you trying to do? Because this seems a bit goofy to me, all this bit manipulation and such. Even though it's a short program, it just seems to me like you'll get yourself stuck in future trying to figure out what you were trying to do in the first place.

[oneohthree]

This is a part of the 2 way paging system that I am doing for a project. Basically what I am trying to do is take 4 bits from the transmitter that I get at the receiver end and do some operations on it. I am assuming that the first two bits are the address and the last two bits are the mode. There are two modes tracking and finding. In each case, I am first checking the last two bits to see which mode it is. After I do that, I am checking if the first two bits of address matches. If the address matches, it will change the third bit (kind of like an acknowledgement) and output the result somewhere. If it does not match it will not change the code and output it back. In the find mode, it does the same thing except it will make a pin high in order to set off an alert like a LED. Is this making any sense?

[skimask]

This is a part of the 2 way paging system that I am doing for a project. Basically what I am trying to do is take 4 bits from the transmitter that I get at the receiver end and do some operations on it. I am assuming that the first two bits are the address and the last two bits are the mode. There are two modes tracking and finding. In each case, I am first checking the last two bits to see which mode it is. After I do that, I am checking if the first two bits of address matches. If the address matches, it will change the third bit (kind of like an acknowledgement) and output the result somewhere. If it does not match it will not change the code and output it back. In the find mode, it does the same thing except it will make a pin high in order to set off an alert like a LED. Is this making any sense?

Ok, that makes a bit more sense....
A bit (pun intended) simpler, maybe????......
Take a sent byte...invert it and send it back as some sort of acknowledge.
For instance: (using 4 bits, $5, $A, $0, $F, are already taken, so can't use those)
Send $1, return $E, acknowledged
Send $2, return $D, and so on...
Anything else returned would be 'not' acknowledged...
Leaves you with $1,2,3,4,6,7 for send codes ($E,D,C,B,9,8 for returned codes).... if 6 codes is enough for you...
That way you could set the 'address' for each pager/receiver with 3 DIP switches (with 2 unused combo's)...

[oneohthree]

Would it matter if I used t2400 or n2400 in my code for serin/serout? I used n2400 in my code and everything is encoding and decoding correctly. I know this because the number at the receiver checks when I write the result into EEPROM and convert the hexadecimal to binary. Also, it seems like the receiver code does not go to the if statements at the end. For example, if I receive 1100 it serout something to pin 1. When I put a LED at pin 1 I don't see anything. Is there anyway I can fix it? Would I have to change my decoded message from hexadecimal to binary in order to allow me to manipulate the bits?

'Transmitter Code
'Transmitter Code
Include "Modedefs.bas"
main:
v var byte : counter var byte : encoded var byte : v = %1100
'Manchester encoding
For counter = 0 to 3
If v.0[counter]=0 Then
encoded.0[counter*2]=0 : encoded.0[counter*2+1]=1 'If it is a zero make the first bit 0 and second bit 1
Else
encoded.0[counter*2]=1 : encoded.0[counter*2+1]=0 'If not then make first bit 1 and second bit 0
EndIf
Next counter : serout PORTB.0, n2400, [ $55 , $55 ,$aa , encoded ] 'send out code
write 0, encoded
High 1
Pause 1000
Low 1
goto main


'Receiver Code
Include "Modedefs.bas"
s var byte : B0 var byte : B1 var byte : 's is byte to be encoded, B0 and B1 is byte
counter var byte : cnt55 var byte: 'counter is byte and cnt55 is byte
encoded1 var byte : action var byte : alert var byte : B0=1 : B1=1
'encoded1 word sized variable that holds encoded byte v, alert variable, action variable, B0 and B1 hardwired address
s=0: encoded1=0
main:
cnt55 = 0 'counter for $55 is zero

waitfor55:
serin PORTB.0, t2400, encoded1 'take in data at pin 0 and place in encoded1
if encoded1 = $55 then
cnt55 = cnt55 + 1 '$55 read, increase cnt55 by 1
if cnt55 = 2 then goto waitforaa 'if $55 occurs 3 times in a row check for $aa
else
goto main 'if not $55, reset counter at main and restart
endif
goto waitfor55

waitforaa:
serin PORTB.0, n2400, encoded1
if encoded1 <> $aa then goto main 'restart, incorrect leader bit

serin PORTB.0, n2400, encoded1 : serout PORTB.4, n2400, [encoded1] 'take in from pin 0 to encoded 1 output to pin 3 contens in encoded1
write 0,encoded1
High 7
Pause 10000
Low 7


'Decoding
For counter=0 to 3:s.0[counter]=encoded1.0[counter*2]:Next counter
serout PORTB.3, n2400, [s] 'Ouptut decoded message
write 1, s
High 6
Pause 10000
Low 6

'Tracking code
If (s.2==0) & (s.3==0) Then 'if the code matches 00
If (s.0==B0) & (s.1==B1) Then 'if the address matches then
s.2=1: action = s.2: 'set the third bit to 1 and send it back
alert = 0:
serout PORTB.1, n2400, [s] 'output to pin 1 value in s
Else
s.2=0: action = s.2: 'do not change anything and send back
alert = 0:
serout PORTB.2, n2400, [s] 'output to pin 1 value in s
Endif
Endif

'Tracking and Finding code
If (s.2==0) & (s.3==1) Then 'if code matches 01 then
If (s.0==B0) & (s.1==B1) Then 'If the address matches then
s.2=1: action=s.2: 'set the third bit to 1 and send back
alert=1:
serout PORTB.6, n2400, [s]: 'output to pin 1 value in s
High 2 'set alert to 1 and make pin 2 high.
Else
s.2=0: action=s.2: 'do not change anything and send back
alert=0:
serout PORTB.5, n2400, [s] 'output to pin 1 value in s
Endif
Endif

[skimask]

'Transmitter Code
Include "Modedefs.bas"
main:
v var byte : counter var byte : encoded var byte : v = %1100
'Manchester encoding
For counter = 0 to 3
If v.0[counter]=0 Then
encoded.0[counter*2]=0 : encoded.0[counter*2+1]=1 'If it is a zero make the first bit 0 and second bit 1
Else
encoded.0[counter*2]=1 : encoded.0[counter*2+1]=0 'If not then make first bit 1 and second bit 0
EndIf
Next counter : serout PORTB.0, n2400, [ $55 , $55 , $55 , $55 , $55 , $55 ,$aa , encoded ] 'send out code
write 0, encoded
High 1
Pause 1000
Low 1
goto main


'Receiver Code
Include "Modedefs.bas"
s var byte : B0 var byte : B1 var byte : 's is byte to be encoded, B0 and B1 is byte
counter var byte : cnt55 var byte : cntaa var byte 'counter is byte and cnt55 is byte
encoded1 var byte : action var byte : alert var byte : B0=1 : B1=1
'encoded1 word sized variable that holds encoded byte v, alert variable, action variable, B0 and B1 hardwired address
s=0: encoded1=0
main:
cnt55 = 0 : cntaa = 0 'counter for $55 & $aa is zero

waitfor55:
serin PORTB.0, t2400, encoded1 'take in data at pin 0 and place in encoded1
if encoded1 = $55 then
cnt55 = cnt55 + 1 '$55 read, increase cnt55 by 1
if cnt55 > 3 then goto waitforaa 'if $55 occurs more than 3 times in a row check for $aa
else
goto main 'if not $55, reset counter at main and restart
endif
goto waitfor55

waitforaa:
serin PORTB.0, n2400, encoded1
if encoded1 <> $aa then
cntaa = cntaa + 1
if cntaa > 5 then goto main 'restart, incorrect leader bit
endif
serin PORTB.0, n2400, encoded1 : serout PORTB.4, n2400, [encoded1] 'take in from pin 0 to encoded 1 output to pin 3 contens in encoded1
write 0,encoded1
High 7
Pause 10000
Low 7


'Decoding
For counter=0 to 3:s.0[counter]=encoded1.0[counter*2]:Next counter
serout PORTB.3, n2400, [s] 'Ouptut decoded message
write 1, s
High 6
Pause 10000
Low 6

'Tracking code
If (s.2==0) & (s.3==0) Then 'if the code matches 00
If (s.0==B0) & (s.1==B1) Then 'if the address matches then
s.2=1: action = s.2: 'set the third bit to 1 and send it back
alert = 0:
serout PORTB.1, n2400, [s] 'output to pin 1 value in s
Else
s.2=0: action = s.2: 'do not change anything and send back
alert = 0:
serout PORTB.2, n2400, [s] 'output to pin 1 value in s
Endif
Endif

'Tracking and Finding code
If (s.2==0) & (s.3==1) Then 'if code matches 01 then
If (s.0==B0) & (s.1==B1) Then 'If the address matches then
s.2=1: action=s.2: 'set the third bit to 1 and send back
alert=1:
serout PORTB.6, n2400, [s]: 'output to pin 1 value in s
High 2 'set alert to 1 and make pin 2 high.
Else
s.2=0: action=s.2: 'do not change anything and send back
alert=0:
serout PORTB.5, n2400, [s] 'output to pin 1 value in s
Endif
Endif

Try that out. Send more $55's for the leader (more time for RX to sync up), wait for at least 3 of them. When you get 3, start watching for an $AA. If you don't get an $AA within 5 bytes, restart the process.

As far as changing hex to binary...PBP doesn't care one way or the other. You are working with a byte. PBP can work on bytes, bits, hex, binary, doesn't matter. Just a matter of looking up the right math operator and using it.

[oneohthree]

The encoding and decoding works properly, I have 4 $55's now. I also changed my logic around in my receiver code so that it checks the address (check the first two bits) then determines the mode (checks the last two bits). But, I discover that my microcontroller repeatedly doesn't execute the logic correctly. Even if the first two bits match it always jumps to the statement (indicated by the **** in my code) where it writes to the third memory location in the EEPROM.
I do not understand why it does that.

Receiver code:

Include "Modedefs.bas"
s var byte : B0 var bit : B1 var bit : 's is byte to be encoded, B0 and B1 is byte
counter var byte : cnt55 var byte: 'counter is byte and cnt55 is byte
encoded1 var byte : action var byte : alert var byte : B0=1 : B1=1
'encoded1 word sized variable that holds encoded byte v, alert variable, action variable, B0 and B1 hardwired address
s=0: encoded1=0

main:
cnt55 = 0 'counter for $55 is zero

waitfor55:
serin PORTB.0, t2400, encoded1 'take in data at pin 0 and place in encoded1
if encoded1 = $55 then
cnt55 = cnt55 + 1 '$55 read, increase cnt55 by 1
if cnt55 = 4 then goto waitforaa 'if $55 occurs 4 times in a row check for $aa
else
goto main 'if not $55, reset counter at main and restart
endif
goto waitfor55

waitforaa:
serin PORTB.0, n2400, encoded1
if encoded1 <> $aa then goto main 'restart, incorrect leader bit

serin PORTB.0, n2400, encoded1 : 'serout PORTB.4, n2400, [encoded1] take in from pin 0 to encoded 1 output to pin 3 contens in encoded1
write 0,encoded1
High 7
Pause 2000
Low 7


'Decoding
For counter=0 to 3:s.0[counter]=encoded1.0[counter*2]:Next counter
serout PORTB.3, n2400, [s] 'Ouptut decoded message
write 1, s
High 6
Pause 2000
Low 6


if (s.0=1) AND (s.1=1) then 'Check if address matches
goto L2
else *****
write 3, s
High 2
Pause 2000
Low 2
End
endif


L2:
if (s.2=0) And (s.3=0) then 'if the address Tracking then
s.2=1: action = s 'set the third bit to 1 and send it back
alert = 0: serout PORTB.1, n2400, [action] 'output to pin 1 value in s
write 2, action
High 1
Pause 2000
Low 1
endif

if (s.2=0) AND (s.3=1) then 'If the address Tracking and Finding then
s.2=1: action=s 'set the third bit to 1 and send back
alert=1: serout PORTB.4, n2400, [action]: 'output to pin 1 value in s
write 4, action
High 4
Pause 2000
Low 4
endif

End

[skimask]

if (s.0=1) AND (s.1=1) then 'Check if address matches
goto L2
else *****
write 3, s
High 2
Pause 2000
Low 2
End
endif



Why is there an 'End' in the middle of your code?

[oneohthree]

If the address (first two bits) don't match then I would end the program. I took that out but it seems like it is not advancing towards the correct loop. When my decoded data is stored in the byte s the first bit of my sequence should be coded a s.0 or do I have to define something else before doing s.0?

Include "Modedefs.bas"
s var byte : B0 var bit : B1 var bit : 's is byte to be encoded, B0 and B1 is byte
counter var byte : cnt55 var byte: 'counter is byte and cnt55 is byte
encoded1 var byte : action var byte : alert var byte : B0=1 : B1=1
'encoded1 word sized variable that holds encoded byte v, alert variable, action variable, B0 and B1 hardwired address
s=0: encoded1=0

main:
cnt55 = 0 'counter for $55 is zero

waitfor55:
serin PORTB.0, n2400, encoded1 'take in data at pin 0 and place in encoded1
if encoded1 = $55 then
cnt55 = cnt55 + 1 '$55 read, increase cnt55 by 1
if cnt55 = 4 then goto waitforaa 'if $55 occurs 4 times in a row check for $aa
else
goto main 'if not $55, reset counter at main and restart
endif
goto waitfor55

waitforaa:
serin PORTB.0, n2400, encoded1
if encoded1 <> $aa then goto main 'restart, incorrect leader bit

serin PORTB.0, n2400, encoded1 : 'serout PORTB.4, n2400, [encoded1] take in from pin 0 to encoded 1 output to pin 3 contens in encoded1
write 0,encoded1
High 7
Pause 2000
Low 7


'Decoding
For counter=0 to 3:s.0[counter]=encoded1.0[counter*2]:Next counter
'serout PORTB.3, n2400, [s] 'Ouptut decoded message
write 1, s
High 6
Pause 2000
Low 6


if (s.bit0=0) AND (s.bit1=1) then 'Check if address matches
goto L3
else
write 2,s
High 2
Pause 2000
Low 2
endif


L3:
if (s.bit2=0) And (s.bit3=0) then 'if the address Tracking then
s.bit2=1: action = s 'set the third bit to 1 and send it back
alert = 0: 'serout PORTB.1, n2400, [action] 'output to pin 1 value in s
write 3, action
High 1
Pause 2000
Low 1
endif

if (s.bit2=0) AND (s.bit3=1) then 'If the address Tracking and Finding then
s.bit2=1: action=s 'set the third bit to 1 and send back
alert=1: 'serout PORTB.4, n2400, [action]: 'output to pin 1 value in s
write 4, action
High 4
Pause 2000
Low 4
endif

End

[skimask]

Are you sure that you are receiving at the RX the same thing you are sending at the TX?


'Decoding
For counter = 0 to 3 : s.0[counter] = encoded1.0[counter * 2 + 1] : Next counter

Try that and see what happens...for grins...

[oneohthree]

I think I figured it out I was reading the bits the wrong way. For example, when I　send 2345 I originally assumed that s.0=2, s.1=3, s.2=4 and s.3=5 but it was in fact the other way. My code now works 90% of the time, occasionally my program will jump to if statements that it is not supposed to go to and write data there.

[skimask]

I think I figured it out I was reading the bits the wrong way. For example, when I　send 2345 I originally assumed that s.0=2, s.1=3, s.2=4 and s.3=5 but it was in fact the other way. My code now works 90% of the time, occasionally my program will jump to if statements that it is not supposed to go to and write data there.

If you're using the RF link, try the straight serial connection first. You can keep the encoding in there.
If it still doesn't work, check your oscillators. If you're using the internal oscillators, probably should go to a crystal.

[oneohthree]

I'm using a 4 MHz crystal oscillator. I'm sure that the stuff is encoding and decoding correctly since it is written correctly in my EEPROM and my logic works most of the time. It seems like my program is executing straight down and is going through incorrect if loops sometimes. For example, when I enter 0101 but somehow my microcontroller will write in memory location 3 and 4. It is only supposed to write in memory location 4. Is there anyway to clear the memory before I start my program? Also, is there anyway that I can prevent it from executing through other if loops? I have attached my new code below.

Receiver code:
Include "Modedefs.bas"
s var byte : B0 var bit : B1 var bit : 's is byte to be encoded, B0 and B1 is byte
counter var byte : cnt55 var byte: 'counter is byte and cnt55 is byte
encoded1 var byte : action var byte : alert var byte : action2 var byte: B0=1 : B1=1
'encoded1 word sized variable that holds encoded byte v, alert variable, action variable, B0 and B1 hardwired address
s=0: encoded1=0

main:

maina:
cnt55 = 0 'counter for $55 is zero

waitfor55:
serin PORTB.0, n2400, encoded1 'take in data at pin 0 and place in encoded1
if encoded1 = $55 then
cnt55 = cnt55 + 1 '$55 read, increase cnt55 by 1
if cnt55 = 4 then goto waitforaa 'if $55 occurs 4 times in a row check for $aa
else
goto maina 'if not $55, reset counter at main and restart
endif
goto waitfor55

waitforaa:
serin PORTB.0, n2400, encoded1
if encoded1 <> $aa then goto maina 'restart, incorrect leader bit

serin PORTB.0, n2400, encoded1 : 'serout PORTB.4, n2400, [encoded1] take in from pin 0 to encoded 1 output to pin 3 contens in encoded1
write 0,encoded1
High 7
Pause 2000
Low 7


'Decoding
For counter=0 to 3:s.0[counter]=encoded1.0[counter*2]:Next counter
'serout PORTB.3, n2400, [s] 'Ouptut decoded message
write 1, s
High 6
Pause 2000
Low 6


if ((s.3==0) && (s.2==1)) then 'Check if address matches
goto L3
else
write 2,s
High 2
Pause 2000
Low 2
End
endif


L3:
if ((s.1==0) && (s.0==0)) then 'if the address Tracking then
action = s: action.1=1'set the third bit to 1 and send it back
alert = 0: 'serout PORTB.1, n2400, [action1] 'output to pin 1 value
write 3, action
High 1
Pause 2000
Low 1
endif

if ((s.1==0) && (s.0==1)) then 'If the address Tracking and Finding then
action2 = s:action2.1=1 'set the third bit to 1 and send back
alert=1: 'serout PORTB.4, n2400, [action2]: 'output to pin 1 value i
write 4, action2
High 4
Pause 2000
Low 4
endif

End

[skimask]

It seems like my program is executing straight down and is going through incorrect if loops sometimes.

Well, yes, it is going to execute straight down (as it's laid out here in the forums). Read thru it. How is it supposed to NOT execute straight down? There's no jumps back to the main loop or anything anywhere (except for where the serial data is received).

[oneohthree]

For my code, I use If ((s.3==0) && (s.2==1)) then
goto L3

Is it better to place L3 before the if statement or after it?
Is it a good idea to do If ((s.3==0) && (s.2==1)) or should I separate the if statement?

[skimask]

For my code, I use If ((s.3==0) && (s.2==1)) then
goto L3

Is it better to place L3 before the if statement or after it?
Is it a good idea to do If ((s.3==0) && (s.2==1)) or should I separate the if statement?

If ( s.3 = 0 ) and ( s.2 = 1 ) is fine. (In practice I don't use ==, I always use =, same thing for the &&, I always use 'AND', easier to read)

If you think the L3 before the if will work better, then try it.