PIC to PIC TX RX and PIC to PC COM RX ..a little help please

**dhouston** · - 5th December 2009, 22:33

Originally Posted by Dennis

I would say the receiver get's maybe one in every 50 sent packets, if I'm lucky ;-(

You need 2-3m physical separation between TX & RX. Otherwise, the superregenerative receiver and the transmitter will interfere with each other.

**Dennis** · - 5th December 2009, 22:52

Hi Dave Houston

Thanks million for the reply.

I have them even farther apart >3m
If I am closer I receiver more transmitted frames, as I move further so the number decreases.

I tried the same transmitter and receivers using your code as well but have no success when I use it but it does work when the two PICS are connected by wire !

I will most certainly try increasing or reducing the range...
and then update a little later :-)
I will also try your code using the PIC 12F629's as well

If you have any more suggestions I would happily try them and submit feedback

Thanks again

Dennis

**mackrackit** · - 6th December 2009, 00:46

I think the modules you are using are the same as Bruce sells, the RWS/TWS ones?
What are you using for an antenna and how long is it? Should be around 6.5 inches. Ground plane? Anything around that could be causing interference? A picture of the setup might help.

Can you post the code that is sorta working? At this point it could be a number of things. We have to rule out hardware or software.

Now try to tighten things up a bit.

Code:

TRAIN  VAR BYTE
train =  $B3
SYNK VAR BYTE
SYNK = $7E

SEROUT2 PORT??, BAUD?,[TRAIN, SYNK, DEC 23]

Code:

SYNK VAR BYTE
SYNK = $7E
MYVAR  VAR BYTE

SERIN2  PORT??, BAUD?, [WAIT(SYNK), DEC MYVAR]

**Dennis** · - 6th December 2009, 03:48

Dave :-)

It's working like a charm :-)....I think, just getting an

extra character on every second line :-)
Range is awesome in the house, reaches all distant corners

--will do range tests tomorrow and feedback to you.

Here's the OLD code

Which worked but wasn't too accurate

TX CODE

Code:

TRAIN	VAR BYTE
TRAIN=$55


hSEROUT [TRAIN,TRAIN,TRAIN,TRAIN,TRAIN,"9",dec 3,$d,$a]

RX code

Code:

HSERIN [WAIT("9"),DEC NET]

 HSERout ["I Recived this number ",DEC NET,$d,$a] 'net var 

value should show in hyperterminal

Heres the NEW TX code
USING HSER

Code:

DEFINE HSER_RCSTA 90h ' Enable serial port & continuous 

receive
DEFINE HSER_TXSTA 20h ' Enable transmit, BRGH = 0
DEFINE HSER_SPBRG 207 ' 2400 Baud @ 32MHz, 0.17%
DEFINE HSER_CLROERR 1 ' Clear overflow automatically

test:
TRAIN  VAR BYTE
 train =  $B3
 SYNK VAR BYTE
 SYNK = $7E

hserout [TRAIN,SYNK,DEC 23]
goto test

and the RX code:

Code:

DEFINE HSER_RCSTA 90h ' Enable serial port & continuous 

receive
DEFINE HSER_TXSTA 20h ' Enable transmit, BRGH = 0
DEFINE HSER_SPBRG 207 ' 2400 Baud @ 32MHz, 0.17%
DEFINE HSER_CLROERR 1 ' Clear overflow automatically

test:

high led

hserin [WAIT(SYNK), DEC net]


toggle LED
HSERout ["I Recived this number ",DEC NET,$d,$a] 'net var 

value should show in hyperterminal

goto test

Here's my receiver output from MCS serial tool window

Code:

I Recived this number 2
I Recived this number 23
I Recived this number 2
I Recived this number 23
I Recived this number 2
I Recived this number 23

As you can see I'm receiving DEC 2 and 23.
Where is the number 2 coming from ?
Eerie ?

Now all I need to do is akind of checksum for example, if

the number 23 is received 3 times then it's a VALID TX.

Any more optimizations or tweaks I should try ?

Thanks a million

Kind regards

(From a very happy:-))
Dennis

**mackrackit** · - 6th December 2009, 04:09

COOL!!!!

Probably the easiest thing to do for this app would be a simple check.

Code:

hserin [WAIT(SYNK), DEC net]
IF net = 23 THEN ...

Or build a checksum... but try the above first, keep it simple.

**aratti** · - 6th December 2009, 08:14

Dennis, you should remove the DEC command from the HSEROUT see the code below.

Code:

A0 var BYTE

A0=23
'hserout [TRAIN,SYNK,DEC 23]
hserout [TRAIN,SYNK, A0]

Al.

**Dennis** · - 6th December 2009, 08:55

Hi Al

How are you?

Thanks for the tip will definitely try it :-)

Kind regards

Dennis

**dhouston** · - 6th December 2009, 13:16

Originally Posted by Dennis

I tried the same transmitter and receivers using your code as well but have no success when I use it but it does work when the two PICS are connected by wire !

If it works wired but not wireless, the most likely explanation is that you have something amiss in the way you have connected the TX/RX modules.

**Dennis** · - 6th December 2009, 23:37

Hi Al, Dave and Dave

This appear to be an HSEROUT issue!!

When I use HSERIN with a string before the variables like this - check reciver code HSEROUT line
RECEIVER

Code:

'variables begin here
        A0 var byte
        net var byte
        led var PORTD.0
        SYNK VAR BYTE
        SYNK = $7E

'end of variables

test:

hserin [WAIT(SYNK),DEC net]
    
    
    if net = 23 then 
    lcdout "i got 23 "
    toggle LED
    'lcdout $fe,1
    endif

 HSERout ["got this",DEC net,$d,$a] 'net var show in hyperterminal 

 got test 

end

TRANSMITTER

Code:

 'RF variables
 'A0 var BYTE
 'A0=23
  'TRAIN	VAR BYTE
 'TRAIN=$55
 TRAIN  VAR BYTE
 train =  $B3
 SYNK VAR BYTE
 SYNK = $7E

 'Variables end here

    
loopy:

high LED '  LED on
hserout [TRAIN,SYNK,dec 23]
 low led 'LED off
 Goto loopy  ' Go back to loop and blink LED forever
        End

then the number 23 as well as the number 2 appears !!
See here:

Code:

got this23
got this2
got this23
got this2
got this23
got this2
got this23
got this2
got this23
got this2

If I remove the string of letters , in this case "got this " then every single received line shows only the number 23 which is what we are expecting to see!
See here:

Code:

PERFECT except for once in a while the occasional number like 2 or 3 shows up!

And trying Al's suggestion of removing the DEC modifier (only on receiver side and for both hserin and hserout)
I get this

Code:

got this2
got this2
got this2
got this2
got this2
got this2
got this2
got this2

Now tell me that's not a strange one

Now...some really awesome observations from my tests here :

First off this is working like a charm !
It's pretty damn close to near perfect in terms of reliable data transfer! (would love any further suggestions re checksums -- I though of something like catching a few instanced of the byte and then accepting it as correct!

Range is awesome ! Right now, as I am typing this the Transmitter is outside my house at the edge of the property - well over 200m and I have taken it upstairs and downstairs every little nook and cranny and it's still spot on !

Speed is fantastic - its so fast the led hardly blinks and the MCS serial tool window is filled up in less than a second

I have both receiver and transmitter hooked up to a 9V battery and then into a 5V regulator with no caps anywhere. My entire house is flooded with 2,4 and 5,8 GHz wireless and there are electrical appliances plentifold.

If the receiver is left in powered on happily waiting for it's signal , as the transmitter is powered on the receiver has already caught at least 6 bytes :-) ...this is how wireless should be in a perfect world :-)
I would be happy to report that the combination of train and sync byte are a winner! Spot on Mackrackit - thank you!

I am extremely happy with verything so far and just want to thank all of you who have guided me with code snippets, corrections and everything else!

Thank you so much !!

Dave Houston I will still definitely be getting you code working too, come rain hail or snow!

All that remain (for now :-)) is the ability to send more than one byte.
I was thinking 3 bytes. (24 bits total)
So my question is this:
Assuming I am to stick with this method , what is the best method (most relaible) to be adding more bytes to be sent ?

Thanks yet again

Kind regards

Dennis

**aratti** · - 7th December 2009, 09:28

...And trying Al's suggestion of removing the DEC modifier (only on receiver side and for both hserin and hserout)

Dennis, I suggested you to remove the DEC modifier in Transmitter not in the receiver side.

The reason is that you Tx a pure ascii code and convert it to decimal at the receiver side, while now you are modifying the byte twice (at Tx & at Rx) and can yield wierd results.

Al.

**mackrackit** · - 7th December 2009, 10:36

Thanks Al for pointing out my mistake.

Dennis,
Just for fun, send this straight to the terminal, you might find it interesting.

Code:

XNUM    VAR BYTE[8]
XNUM = 225 'CHANGE THIS NUMBER AS NEEDED

SEROUT2 GPIO.5,16780,[TRAIN,SYNK,DEC XNUM.7,DEC XNUM.6,DEC XNUM.5,_
   DEC XNUM.4,DEC XNUM.3,DEC XNUM.2,DEC XNUM.1,DEC XNUM.0,_
   "--",DEC XNUM,$d,$a]

More bytes?
SEND

Code:

    XNUM    VAR BYTE
    YNUM    VAR BYTE
    ZNUM    VAR BYTE
    
    XNUM = 225
    YNUM = 100
    ZNUM = 4
    START:
    SEROUT2 GPIO.5,16780,[TRAIN,SYNK,XNUM,YNUM,ZNUM,$d,$a]
    PAUSE 5000
    GOTO START

RECEIVE

Code:

    XNUM    VAR BYTE
    YNUM    VAR BYTE
    ZNUM    VAR BYTE
    
    START:
    SERIN2 GPIO.5, 16780,[WAIT(SYNK),XNUM,YNUM,ZNUM]
    
    SEROUT2 GPIO.4,16780,["X-",DEC XNUM," Y-",DEC YNUM," Z-",DEC ZNUM,$d,$a]
    GOTO START

**Dennis** · - 7th December 2009, 19:45

Al thanks a million for the clarity on that one .. will check and feedback !

Dave ... ok just for fun so be it !
And if I get greedy would the Var bytes be num num num ? :-)

Expect Feedback .. results may vary :-0

Kind regards

Dennis

Thread: PIC to PIC TX RX and PIC to PC COM RX ..a little help please

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I have that distance

IT WORKS better than before :-)

Ok will try :-)

uncanny behaviour!!

ok.... just for fun !

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