Problem with 12F629, servo and EEPROM

[skimask]

Skimask - Thanks for the reply. I tried your code but am getting the same result. If the Set Limit Enable switch is on, I can control the servo movement with the pot (I had to change the scaling back to what I originally had, first). When it is at this point, it is not applying the limits (100 & 250). As soon as I turn off the switch (applying the limits), the servo does not move from the current position. It is acting like the minposit and maxposit variables are the same number. And the memory stuff still doesn't work either. This is such a simple design, I am truly baffled... Any other thoughts?

The data statement is wrong-ish...
data @0,100,250
The original would put: 0,100,250 into eeprom, this way puts 100,250 starting at location 0.

And you might want to try 'unrolling' your code, put it all in-line, get rid of the gosub. I believe if you 'unroll' your code, you may find your logic problem. Then you can put it back into a more modular format.

[Acetronics2]

Hi, Atom

Those lines Have Passed the MPSIM Test ...

@ DEVICE pic12F629, INTRC_OSC_NOCLKOUT ; Using Internal Clock, no clock out
@ DEVICE pic12F629, WDT_ON ; Enable Watch dog timer
@ DEVICE pic12F629, PWRT_ON ; Enable Power-up timer
@ DEVICE pic12F629, MCLR_OFF ; Disable MCLR pin 
@ DEVICE pic12F629, BOD_ON ; Enable Brown-out detect
@ DEVICE pic12F629, CPD_OFF ; EEPROM Protect
@ DEVICE pic12F629, PROTECT_OFF ; Code Protect off

'@ __CONFIG _INTRC_OSC_NOCLKOUT &  _WDT_ON & _PWRTE_ON & _BODEN_ON & _MCLRE_OFF

DEFINE OSCCAL_1K 1
DEFINE BUTTON_PAUSE 20

GPIO	= %00000000
TRISIO 	= %11111110

INTCON.6=0 ' Disable all unmasked Interrupts
INTCON.7=0 ' Disable Global Interrupts
CMCON = 7 ' Disable analog comparator

ServoOut 	var GPIO.0
SetLimitSw 	var GPIO.1
PotIn 		var GPIO.2
MinSw 		var GPIO.4
MaxSw 		var GPIO.5

Delay		var Byte

Posit 		var Byte
MinPosit 	var Byte
MaxPosit 	var Byte

'load starting min and max positions at program time
data @ 0,100 
data @ 2,250 

'************************************************* ***************
low Servoout

'read in stored min and max limits

read 0, MinPosit
read 2, MaxPosit

Start:

gosub GetServoPosition

Low 	servoout
pulsout servoout, posit



Delay = 0
BUTTON setlimitsw, 0, 255, 0, Delay, 1, Start

	Delay = 0
	BUTTON minsw, 1, 255, 0, Delay, 1, MinL		'20 ms
	Delay = 0
	BUTTON maxsw, 1, 255, 0, Delay, 1, MaxL		' 20 ms
	
	pause 20					' no button pushed
	Goto Start					
	
MinL:
	IF maxsw = 1 THEN Start		'1 Button pushed at a Time !!!
	
	IF Posit <> MinPosit THEN
	
		MinPosit = Posit
		write 0, MinPosit						'10 ms
	
	ENDIF
	
goto start

MaxL:
	
	IF minsw = 1 THEN Start		'1 Button pushed at a Time !!!
	
	IF Posit <> Maxposit THEN
	
		MaxPosit = Posit
		write 2, MaxPosit						' 10 ms
		
	ENDIF

goto start

'************************************************* ***************
GetServoPosition:

high potin
pause 1
rctime potin, 1, Posit 'at 4 mhz, returns 3 - 123 :: 1.23 ms max

'adjust posit to get values between 75 and 250
posit = posit + 75 + (posit / 2)

'now limit posit to 100 - 250 (1 ms - 2.5 ms)

if posit < 100 then posit = 100
if posit > 250 then posit = 250

if setlimitsw = 0 then 'apply limits

	if Posit < MinPosit then Posit = MinPosit
	if Posit > MaxPosit then Posit = MaxPosit
	
endif 

return 

'************************************************* ***************

End

Try those lines ... should work !!!

Alain

[Atom058]

Alain - Thanks for your suggestion. I tried it and got different results. Still getting good servo response to the pot, but it does not seem to be registering the min and max values when the buttons are pressed. The servo continues to move to the full limits.

Just to be clear, the SetLimitSw is a slide switch. When it is slid to the On position, the program will monitor for the pressing of either the min or max pushbuttons (momentary). When the SetLimitSw is slid to Off, the program will apply the limits that were set.

The concept is so simple (at least should be) that I am embarassed that I can't get this to work - I have done projects that are a hundred times more complex than this. I know the answer is staring me in the face - I just can't see it!

I appreciate all the comments and encourage more!

[Bruce]

You're reading EEPROM values into your word vars in reverse.

data @0, 0, 100
read 0, MinPosit.byte0 ' low byte now = 0
read 1, minposit.byte1 ' high byte now = 100

Then if Posit < MinPosit then Posit = MinPosit will always = true
since MinPosit starts out at 25,600 or 6400h.

[Acetronics2]

Hi,

Did you check ( W/Multimeter ) GPIO 4 and 5 state when your Min and Max Buttons are pushed ???

stupid question , ehhhh ???

MPSIM shows memory is well written ... so, I do suspect a harware problem !!!

I'll give a try with a '675 ... to be sure ( no 629 home ! )

Alain

[Atom058]

Bruce - Good catch on the Data statement (DUH!)! However, if I run my original code as in my first post (with the change in the data statement), I still get the same results: perfect servo movement when first booted up, but when I move the servo to the center position, switch on the SetLimitSw, press the Min button and then switch off the SetLimitSw, the servo no longer responds to the pot - as though both the min and max buttons were pressed at the same position.

I am beginning to think I have some underlying hardware issue (as Alain suggests). I will do some metering to see if I see anything fishy. If I don't, I'm going to rebuild the board with new components. If it still does it after all that, I'll shoot myself! (just kidding!).

Thanks guys - let me know if you think of anything else!

[Atom058]

Well, just as I expected, it was me and yes, I'm embarassed! I started metering the min and max buttons and noticed that if I pressed either button, both pins went high - explaining why the servo just stayed in one spot when either the min or max button was pressed. After scratching my head over how that could possibly be happening, I noticed that my pull-down resistors were put in vertically instead of horizontally. If you look at the circuit diagram in my first post, you will see what I mean. How stupid was that! Anyway, I rotated the resistors and everything works perfectly! Go figure!

I'd like to thank those who helped me and apologize for wasting their time. I knew it would be something like this...

Well, I made a few changes to the code and here it is in it's final form:

@ DEVICE pic12F629, INTRC_OSC_NOCLKOUT ; Using Internal Clock, no clock out
@ DEVICE pic12F629, WDT_ON ; Enable Watch dog timer
@ DEVICE pic12F629, PWRT_ON ; Enable Power-up timer
@ DEVICE pic12F629, MCLR_OFF ; Disable MCLR pin
@ DEVICE pic12F629, BOD_ON ; Enable Brown-out detect
@ DEVICE pic12F629, CPD_OFF ; EEPROM Protect
@ DEVICE pic12F629, PROTECT_OFF ; Code Protect off

TRISIO = %11111110
INTCON.6=0 ' Disable all unmasked Interrupts
INTCON.7=0 ' Disable Global Interrupts
CMCON = 7 ' Disable analog comparator

ServoOut var GPIO.0
SetLimitSw var GPIO.1
PotIn var GPIO.2
MinSw var GPIO.4
MaxSw var GPIO.5

wPosit var word
Posit var byte
MinPosit var byte
MaxPosit var byte

'load starting min and max positions
data @ 0, 100
data @ 1, 250

'************************************************* ***************
low Servoout

'read in stored min and max limits
read 0, MinPosit
read 1, MaxPosit

'for power-on reset of positions:
if minsw = 1 then
minposit = 100
write 0, minposit
endif
if maxsw = 1 then
maxposit = 250
write 1, maxposit
endif
pause 1000

Start:
gosub GetServoPosition
pulsout servoout, posit
pause 20

if setlimitsw = 1 then 'check min max buttons
if minsw = 1 then
MinPosit = Posit
write 0, MinPosit
pause 250
endif

if maxsw = 1 then
MaxPosit = Posit
write 1, MaxPosit
pause 250
endif
endif

goto start

'************************************************* ***************
GetServoPosition:
high potin
pause 1
rctime potin, 1, wPosit 'at 4 mhz, returns 0 - 120

'adjust posit to get values between 75 and 250
'use word-sized variable because calculation might exceed 255
wposit = wposit + 75 + (wposit / 2)

'now limit posit to 100 - 250 (1 ms - 2.5 ms)
'and put into byte-sized variable
if wposit > 250 then
posit = 250
else
posit = wposit
endif

if posit < 100 then posit = 100

if setlimitsw = 0 then 'apply limits
if Posit < MinPosit then Posit = MinPosit
if Posit > MaxPosit then Posit = MaxPosit
endif

return

'************************************************* ***************

End

[BrianT]

PULSOUT is a toggle. Sooner or later you will get some interference that flips the state of the SERVOOUT line and your system will be off in the weeds.

To guarantee correct working of the PULSOUT command you should first force the SERVOOUT line to a defined state.

For example, put
SERVOOUT = 0
or
LOW SERVOOUT
before calling the Pulsout command.

One of my RC aircraft went berserk because of that little oversight.

HTH
Brian