Problem with 12F629, servo and EEPROM

[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

[skimask]

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

You mean like pulling UP out of an inverted low pass?
I lost a hopped-up clipped wing (+an extra bay) Goldberg Cub that way....(sigh)....

[Acetronics2]

Hi, BrianT

To fullfill your Pulsout knowledge ...

You are to use LOW Output ...

with some Hot plugged servos ( Graupner i.e.) or High capacitive loads ( some µF ) , Output = 0 is not enough to have a neat O level prior to Pulsin.
I know it's not supposed to happen in flight ... but, ...

Service,Sir ...

Alain