BS2 to Prop RF communications

Earl Foster · 2009-01-30 01:05

I am trying to establish communications between a BS2px and the Prop using·a Parallax 433 MHz RF receiver and matching transmitter but I·am having a little difficulty with the coding on the Prop side of things.·

I have communications working between·2·BS2 stamps from an earlier weather station project so I am pretty sure the·pbasic code is ok.· It is·provided below.

Main:
  GOSUB Compass_Get_Axes       ' Get x, and y values
  angle = x ATN -y             ' Convert x and y to brads
  angle = angle */ 361         ' Convert brads to degrees
  COUNT 2, 8710, Counts        ' Count cycles on pin 2 for 2.5 seconds
                               ' Counts = MPH
  'Scale of vortex is 2.5 mph per revolution per second
  PULSOUT 1, 1200 'Sync pulse for the receiver
  SEROUT 1, 396, [noparse][[/noparse] "$HAPB", Counts.HIGHBYTE, Counts.LOWBYTE, angle.HIGHBYTE, angle.LOWBYTE, "^"]
GOTO main

I·am also using my SPIN gps code that is·modified to match the transmitted data, or so I think I do.··The code works·fine with a GPS but not with the RF receiver.· The program does not see the starting delimiter "$" and continues to display·a·series of 12 periods then pauses for ~2.5 seconds then·repeats the cycle.· I do have a 1K resister on the data pin 16 to protect the Prop.· Here is my code

CON
  _clkmode = xtal1 + pll16x                             ' use crystal x 16
  _xinfreq = 5_000_000                                  ' 5 MHz cyrstal (sys clock = 80 MHz)
var
  byte holder[noparse][[/noparse]8], RFR[noparse][[/noparse]8], index, found
  word wSpeed, wDirection
obj
  debug:        "fullduplexserial"             'Parallax object
  RFReceiver:   "fullduplexserial"
PUB main
  debug.start(31, 30, 0, 9600)
  RFReceiver.start(16, 17, 0, 9600)            'Have tried different bit modes
  debug.str(string(13,"Starting Program", 13))
    repeat
       get_RF
       debug.str(string(13,"Windspeed..."))
       debug.dec(wSpeed)
       debug.str(string(13,"Direction..."))
       debug.dec(wDirection)
       
pub get_RF
{{
   Procedure captures specific RF signals.
}}
  bytefill(@holder, 0, 8)
  found := wSpeed := wDirection:= 0
  repeat until found == 1
    index := 0
    repeat while RFReceiver.rx <> "$"    'Wait for the start of the string
      debug.tx(46)                       'display periods until found
    repeat while index < 9             
       holder[noparse][[/noparse]index++] := RFReceiver.rx  'store the bytes
    if holder[noparse][[/noparse]0] == "H"                  'check to make sure it is from the correct source
       if holder[noparse][[/noparse]1] == "A"                
         if holder[noparse][[/noparse]2] == "P"              
           if holder[noparse][[/noparse]3] == "B"            
              index := 0
              repeat until RFR[noparse][[/noparse]index] == "^"  'copy the data
                 RFR[noparse][[/noparse]index] := holder[noparse][[/noparse]index]
                 index++
              found :=  1
  repeat index from 4 to 5           
    wSpeed := wSpeed * 10 + (RFR[noparse][[/noparse]index] - "0") 'Store wind speed
  repeat index from 6 to 7           
    wDirection := wDirection * 10 + (RFR[noparse][[/noparse]index] - "0")   'Store wind direction

I have changed bit modes in the command RFReceiver.start(16, 17, 0, 9600) to see if that made any difference and when I change it to a 1 or 3 I get continous periods without any pauses.·

Can someone tell me what I am doing wrong between the 2 devices?·

Thanks

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StefanL38 · 2009-01-30 17:32

Hello Earl,

your receiver method is quite complex in that way that many conditions have to be true until everything works

for debugging I would simplify the conditions as much as possible.

This means

first test:

simply receive bytes regardless of their value and echo EVERY byte received on your debug-connection

if this works properly add debugoutput to EVERY stage of your conditions

  found := wSpeed := wDirection:= 0
  debug.str(string("found := wSpeed := wDirection:= 0"))

  repeat until found == 1
    debug.str(string("repeat until found == 1 is TRUE"))

    index := 0
    repeat while RFReceiver.rx <> "$"    'Wait for the start of the string
      debug.tx(46)                       'display periods until found
    repeat while index < 9            
       holder[noparse][[/noparse]index++] := RFReceiver.rx  'store the bytes
      debug.str(string("holder[noparse][[/noparse]index++] := RFReceiver.rx"))
      debug.str(string("holder[noparse][[/noparse]"))
      debug.dec(index - 1)
      debug.str(string("] ="))
      debug.tx(holder[noparse][[/noparse]index - 1])
      debug.tx(13)

    if holder[noparse][[/noparse]0] == "H"                  'check to make sure it is from the correct source
      debug.str(string("if holder[noparse][[/noparse]0] == H is TRUE"))
       if holder == "A"               
        debug.str(string("if holder == A is TRUE"))

         if holder == "P"             
'etc etc.
           if holder == "B"           
              index := 0
              repeat until RFR[noparse][[/noparse]index] == "^"  'copy the data
                 RFR[noparse][[/noparse]index] := holder[noparse][[/noparse]index]
                 index++

to see what's happening in detail

best regards

Stefan

Earl Foster · 2009-01-30 18:12

StefanL38 - I found my simple test in/out program I used for my original gps testing.

con
  _clkmode = xtal1 + pll16x      'must be used for the Spin stamp pll8x
  _xinfreq = 5_000_000         'must be used with the Spin stamp 10,000,000
obj
  debug[noparse][[/noparse]2]:        "FullDuplexSerialPlus"           'Debug object
  
pub main
    Debug[noparse][[/noparse]0].start(31, 30, 0, 9600)        'Start the debug terminal
    debug[noparse][[/noparse]0].str(string("Starting"))
    waitcnt(clkfreq + cnt)
    debug[noparse][[/noparse]1].start(16,17,0,9600)             'Start comm to gps
                                           'I have tried all bit modes
    repeat
       debug[noparse][[/noparse]0].tx(debug[noparse][[/noparse]1].rx)           'Receive btye and display
       'waitcnt(clkfreq + cnt)

and I simplified my BS2 code to send out a simple string

  PULSOUT 1, 1200 'Sync pulse for the receiver
  SEROUT 1, 396, [noparse][[/noparse]"$HAPB"]

but still it is not working properly.· The prop displays the same garbage·every 2.5 seconds so it seems to be receiving the information.

#
 ZhÔB

I wonder if I need to hook up the RF differently with the prop.· Currently I have the data connection going through a 1k resistor connected to pin 16.· The RF unit requires +5v.· I will continue to play.

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Earl Foster · 2009-01-30 21:34

After hours of playing around with my code I decided·to change·serial objects that I was using from FullDuplexSerial to Simple_Serial·and now it is working properly.

The object code is so very different that I can not even begin to understand why one works and the other does not.· I am just glad that it is working now.

Thanks and now I can continue with my new project ...

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BS2 to Prop RF communications

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