PropBasic: Quadrature Encoder Help Please

skynugget · 2011-01-16 11:09

hey all, im trying to decode a standard quadrature encoder, and im soooo close.

the code below seems to only count in a negative direction no matter which way i turn the encoder.
i suspect im not masking the bits right before i check for the direction.

does anyone see the mistake in the following test program? thanks so much!

DEVICE          P8X32A, XTAL1, PLL16X
XIN             5_000_000

Baud 		CON 		"T9600"

Encoder   PIN   10..11   INPUT
TX           PIN   30         HIGH

LOAD "serial.lib"

	idx			var		long
	tmp			var		long
	tmp1			var		long
	tmp2			var		long
	
	encNew		var		long
	encOld		var		long
	encVal		var		long	
	
' ======================================================================
  PROGRAM Start
' ======================================================================

Start:
  ' init

Main:
  encNew = Encoder					'get incoder bits
  
  tmp = encOld ^ encNew				'did it change?
  IF tmp = 0 THEN skip				'no so skip
  	
  encOLD = encOLD << 1				'align
  encOLD = encOLD ^ encNew		        'check direction
  tmp1 = encOLD & %00000010		        'iso bit1 
 
  IF tmp1 = 1 THEN					'going up
  	INC encVal					'add to value
  ELSE							'going down	
  	DEC encVal					'subtract from value
  ENDIF
  	
  encOLD = encNew					'save last input
  
  skip:	
  TX_DEC encVal					'debug value
  TX_BYTE 1						'debug home

  
GOTO Main
END

skynugget · 2011-01-17 18:17

got it! it seems to work real nice. thanks all

Main:
	
  encNew = Encoder						'get incoder bits
  encChk = encOld ^ encNew				'did it change?
  
  IF encChk > 0 THEN 					'yes, accumulate
  	encOLD = encOLD & %00000001		'iso bit.0 of old value
  	encChk = encNew >> 1				'iso bit.1 of new value
  	encDir = encold ^ encChk			        'xor magic
		IF encDir = 1 THEN				'going up
  		INC encVal					'add to value
  	ELSE							'going down	
  		DEC encVal					'subtract from value
  	ENDIF
  ENDIF
  
  encOLD = encNew						'save last input
  TX_DEC encVal						'debug value
  TX_BYTE 1							'debug home
	
GOTO Main
END

Bean · 2011-01-18 06:08

Oops, Sorry I missed this thread.
Glad you got it working and thanks for posting the working code. So many forget to do this and really helps others out.

Bean

Sapieha · 2011-01-18 07:33

Hi skynugget
Thanks

@Bean. Its my opinion to: At every time anyone POST (Solved) --- Them can Post how them solved it.

That can help many Beginners to found theirs problems.

And thanks for PBasic.

Bean wrote: »

Oops, Sorry I missed this thread.
Glad you got it working and thanks for posting the working code. So many forget to do this and really helps others out.

Bean

skynugget · 2011-01-18 10:28

Bean wrote: »

Oops, Sorry I missed this thread.
Glad you got it working and thanks for posting the working code. So many forget to do this and really helps others out.

Bean

no worries boss, there are lots of threads to manage

. without people posting problems, solutions and snippets, i never would have been able to get started with microcontrollers, i try to post everything i can so that someday i may return the favor.

$WMc% · 2011-01-18 13:27

skynugget wrote: »

no worries boss, there are lots of threads to manage . without people posting problems, solutions and snippets, i never would have been able to get started with microcontrollers, i try to post everything i can so that someday i may return the favor.

'
Thanks skynugget:
'
I just got a Quadrature encoder set-up last night. I planed to write some code for it this evening in PropBasic.Thanks for the code.
'
I hope you post the Quad-code in the OBEX under PropBasic!
'
Thanks again.

PropBasic: Quadrature Encoder Help Please

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