16F84/16F628 and Manchester

[Navaidstech]

Obviously I missed a few posts.


Thanks for the info there Ioannis.


I searched the forum some more this morning and I was able to whip out a tx/rx pair that ALMOST works, based on code tidbits I found..
At the moment the two modules are connected with wires but once I get the code rectified a bit, I'll move up to RF modules.

I say "ALMOST" because the tx part seems to be working ok, however the receiver isn't quite there yet.

Here is the code that I'm using for transmitting (I have observed it on the oscilloscope and it appears to be working):

dataport var PORTB.0

START:
serout2 PORTB.0,813,[$55, $55, $55, $AA]
mydata = "T"

dataport = $00
pause 1000
goto start


ENCODEMANCHESTER:
ManchesterWord=0
For CounterA=0 to 7
If MyData.0=0 then
ManchesterWord.14=1
else
ManchesterWord.15=1
endif
If CounterA<7 then ManchesterWord=ManchesterWord>>2
MyData=MyData>>1
Next CounterA
serout2 dataport,396,[manchesterword.lowbyte, manchesterword.highbyte]

Return


And here is the receiver code:



RECEPTION var PORTB.0
INFO VAR PORTB.2
ERROR var PORTB.1



START:
manchesterword=0

SERIN2 reception, 813, [WAIT($AA),ManchesterWord.LowByte,ManchesterWord.Hi ghByte]
gosub ManchesterDecode

goto start

ManchesterDecode:
ErrorFlag=0
For CounterA=0 to 7
If ManchesterWord.1=0 then
MyData.7=0
ERROR = 0
If ManchesterWord.0=0 then
ErrorFlag=1
ERROR = 1
endif
else
MyData.7=1
ERROR = 0
If ManchesterWord.0=1 then
ErrorFlag=1
ERROR = 1
endif
endif
ManchesterWord=ManchesterWord>>2
If CounterA<7 then MyData=MyData>>1
NEXT COUNTERA
serout2 info, 813, [Mydata]

Return

I set PORTB.1 as an indicator telling me whether or not the Manchester code has errors in it... I was monitoring that pin with a scope and not once did it light up, yet I'm getting garbage coming out on pin 2.

Somehow I'm thinking that the receiver code is missing something but I'm hoping if you guys could point out where the problem lies.

thanks

Alex

[Ioannis]

I cannot see how these two pieces of code (tx and rx) can work together.

Read your code again,or post the working code.

Or try the untested one that is attached.

Rename to .bas and burn it.

Ioannis

[Navaidstech]

Of course!

I'm sending the preamble at a wrong baud rate! DOH!

Changed it and it works ok now....

thanks!!!

Alex

[Navaidstech]

Ioannis...

looks like I jumped the gun there. Your code seems to be working much better than the one I used.

Thank you for your help. Hopefully I'll be ok from hereon.

Alex

[Ioannis]

...looks like I jumped the gun there...

? I am not sure i follow...

You are welcome!

Ioannis

[Navaidstech]

In my previous message I indicated that once the baud rate was changed, the original program that I posted was working ok.
Then I noticed some errors popping up so I decided to delve further into the program... it didn't look right so I decided to use your untested routines and they worked great.

Thanks again!