Digital Encoder Problems

blittled · 2009-07-02 04:44

I'm using the Boe-Bot Digital Encoder with 10k pull up resistors to 3.3V on the input line and the following code to read them:

Propeller

con 
  _clkmode  = xtal1 + pll16x                'Adjusted for ProtoBoard
  _xinfreq  = 5_000_000
  BaudRate   = 9200
  TxPin = |< 1
  RxPin = |< 0

var
  long CntStack[noparse][[/noparse]40]
  Word counterL 

obj
  Comms  :   "JDCogSerial"  

pub start | val, valHi, valLo
  CommPtr := Comms.start(RxPin, TxPin, BaudRate) ' Start Encoder counting
  cognew (Count(@counterL, 2),@CntStack)
  val := Word[noparse][[/noparse]@counterL]
  valHi := val/256
  valLo := val - valHi*256
  byte[noparse][[/noparse]@Buffer][noparse][[/noparse] 0 ] := valHi
  byte[noparse][[/noparse]@Buffer][noparse][[/noparse] 1 ] := valLo
  SendBuffer

PUB SendBuffer | index
   index~
   Comms.Str(string("!STBD"))
   repeat until index == 2
      Comms.tx(byte[noparse][[/noparse]@Buffer][noparse][[/noparse]index])
      index++

Pub Count(cntrAddr, pin) | status
  dira[noparse][[/noparse]pin] := 0
  word [noparse][[/noparse]cntrAddr] := 0
  status := ina[noparse][[/noparse]pin]
  Repeat
    waitpne(status, pin, 0)
    status := ina[noparse][[/noparse]pin]
    word [noparse][[/noparse]cntrAddr]++

On the receiving end instead of incremental numbers I get random large numbers like 50768, 1238, 17301 when using

Basic Stamp

mbuff   VAR Byte(2)
DO
  SERIN 8,84, [noparse][[/noparse]WAIT("STBD"),STR mbuff\2]
  DEBUG DEC mbuff(0)*256 + mbuff(1)
LOOP

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
What electronics need - MORE POWER!!!!!!!

MagIO2 · 2009-07-02 05:03

con 
  _clkmode  = xtal1 + pll16x                'Adjusted for ProtoBoard
  _xinfreq  = 5_000_000
  BaudRate   = 9200
[color=red]  TxPin = |< 1
  RxPin = |< 0[/color]

var
  long CntStack[noparse][[/noparse]40]
  Word counterL 

obj
  Comms  :   "JDCogSerial"  

pub start | val[color=orange][s], valHi, valLo[/s][/color]
  CommPtr := Comms.start(RxPin, TxPin, BaudRate) ' Start Encoder counting
  cognew (Count(@counterL, 2),@CntStack)
  val := Word[noparse][[/noparse]@counterL]
[s][color=orange]  valHi := val/256
  valLo := val - valHi*256[/color][/s]
  byte[noparse][[/noparse]@Buffer][noparse][[/noparse] 0 ] := [color=orange][s]valHi[/s] byte[noparse][[/noparse]@val][noparse][[/noparse]1][/color]
  byte[noparse][[/noparse]@Buffer][noparse][[/noparse] 1 ] := [color=orange][s]valLo[/s] byte[noparse][[/noparse]@val][noparse][[/noparse]0][/color]
  SendBuffer

PUB SendBuffer | index
   index~
   Comms.Str(string("!STBD"))
   repeat until index == 2
      Comms.tx(byte[noparse][[/noparse]@Buffer][noparse][[/noparse]index])
      index++

Pub Count(cntrAddr, pin) | status, mask
  [color=orange][s]dira[noparse][[/noparse]pin] := 0[/s][/color]            ' simply not needed, as cognew always starts a cog with dira set to 0 completely
  word [noparse][[/noparse]cntrAddr] := 0

  [color=green]mask := |< pin[/color]
  status := ina[s][color=purple][noparse][[/noparse]pin][/color][/s] [color=purple]& mask[/color]
  Repeat
    waitpne(status, [color=red][s]pin[/s][/color][color=green]mask[/color], 0)
    status := ina[color=purple][s][noparse][[/noparse]pin][/s] & mask[/color]
    word [noparse][[/noparse]cntrAddr]++

In red you see the problem! Waitpne expects a bitmask, but what you gave it is the bit-number, so actually it is watching the TxPin which is heavyly used by the serial interface.

PS: forgot something ... see the purple correction. Know the difference? ina[noparse][[/noparse]pin] is shifting bit number pin of ina to bit 0 of status.

Post Edited (MagIO2) : 7/2/2009 5:22:55 AM GMT

Digital Encoder Problems

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