encoder wowes

[Dave]

wallaby, First place these declarations at the top of your program:

' LCD SETUP DEFINES
DEFINE LCD_DREG PORTA ' set LCD data port
DEFINE LCD_DBIT 0 ' set starting bit ( 0 or 4 ) if 4 bit bus
DEFINE LCD_RSREG PORTA ' set LCD register select port
DEFINE LCD_RSBIT 4 ' set LCD register select bit
DEFINE LCD_EREG PORTA ' set LCD enable port
DEFINE LCD_EBIT 5 ' set LCD enable bit
DEFINE LCD_BITS 4 ' set LCD bus size ( 4 or 8 bits )
DEFINE LCD_LINES 2 ' set number of lines on LCD
DEFINE LCD_COMMANDUS 2000 ' set command delay time in us
DEFINE LCD_DATAUS 50 ' set data delay time in us

'******** DEFINE VARIABLES **********
OFS VAR BYTE 'ENCODER + or - COUNT
TEMP1 VAR BYTE 'ENCODER SCRATCH VARIABLE
TEMP2 VAR BYTE 'ENCODER SCRATCH VARIABLE
KNOBLIM VAR WORD 'UP-DOWN COUNTER LIMIT
UP_DOWN VAR WORD 'COUNTER PASS VARIABLE
MULTIPLY VAR BYTE 'KNOB MULTIPLIER FOR SPEED

'*********** INITIALIZE VARIABLES ************
Multiply = 1 'set multiplier to 1
Variable = 100 'set variable initially to value of 100
Knoblim = 1000 'set maximum rollover to occur at 1000
TEMP1 = (PORTB & %00000011) << 2 'only executed once to preload temp1


Next, run this code and then rotate the encoder
to see the action. By the way don't forget the A and B outputs from the rotary encoder are wired to PORTB pins 0 and 1 respectively.

loop:'
UP_DOWN = Variable 'make current position equal to value of variable
GOSUB ENCOD 'READ ENCODER
Variable = UP_DOWN 'add up/down count to variable
lcdout $FE,$02,DEC5 Variable
goto loop


'*************************************************
ENCOD: 'READ ROTARY ENCODER POSITION SUBROUTINE
'*************************************************
TEMP2 = TEMP1 | (PORTB & %00000011)
LOOKUP TEMP2,[2,3,1,2,1,2,2,3,3,2,2,1,2,1,3,2],OFS
TEMP1 = (TEMP2 << 2) & %00001100
UP_DOWN = UP_DOWN + ((OFS * MULTIPLY) - (2 * MULTIPLY))
IF UP_DOWN = (KNOBLIM + MULTIPLY) THEN UP_DOWN = 0
IF UP_DOWN > KNOBLIM THEN UP_DOWN = KNOBLIM
MULTIPLY = 1
RETURN

Dave Purola,
N8NTA

[wallaby]

Thanks Dave, I owe you a beer! Will try this out and post results. The 2 metre receiver works a treat, better than .2uv for 12 db sinad and the frontend tracks nicely. It will cover 108 to 161 Mhz.

Cheers from Oz

Nigel Andrews

[wallaby]

Dave,

I tried it out and it is counting nicely, but still in increments of 2! It seems to think that the encoder has transitioned twice ( both going high, albeit one in front of the other ) so it goes up by 2. If you carefully half turn the encoder and make one input go up on its own, it then goes up by one. As soon as you let go and the other goes up, it counts up by one again.

If you can give me a mailing address in the US I will post one off to you free, they are quite a nice encoder and I have a few spare. If you like you can email me direct at [email protected] with your address and I will send it. Might come in handy for a project of yours in the future.

Otherwise I will keep playing around with the test one here.

Cheers

Nigel

[Dave]

Thanks Nigel, I just emailed you my address.

[Dave]

wallaby, I just received the encoder yesterday and it sure looks cool... You didn't tell me that it had a pushbutton on it as well. I'll hook it up this weekend and get back to you on Monday. Once again thanks....

Dave Purola,
N8NTA

[wallaby]

O.K , glad to see it arrived safely.

Cheers

Nigel

[Dave]

Nigel, After hooking up the encoder you sent me and looking at it with a scope I found it is working as advertised. I went to the ALPS website and lo & behold the documentation says it has detents on every other (2 of the 4 states) of the encoder output. That is why the encoder seems to be counting by 2 because it actually is. Attached is the waveform for the output of the encoder at the detents. The suggested connection is 5 volts thru a 10k to the switch. Then a 10k from the switch in series with a .01uF to ground with the connection of the 10k and the .01uF going to the processor. This provides a filter mechanism to counter act any switch bounce that may occure due to the nature of the rotary switch. Once again, Thanks Nigel....

Dave Purola,
N8NTA