Having trouble adding a new object to an existing program and run it in a new cog

Comments

• StephenMoore Posts: 188

  2011-11-13 15:17 edited 2011-11-13 15:17

  I would try to just get the servo working first. Try this object with a 20 msec cycle time instead of 10msec.

  VAR long servoBuff[10]
      long servoPos
      long servoPin
      long cog
  
  
  
  
  CON
  _clkmode = xtal1 + pll16x                 ' System clock ? 80 MHz
  _xinfreq = 5_000_000                      ' Using 5 MHz external crystal oscillator
  
  
                                            ' Servo signal to this I/O pin-change if needed
  
  
  PUB Start(servo_Pin)
  
  
  servoPin := servo_pin
  cog := cognew(Servo, @servoBuff) + 1
  
  
  
  
  PUB ServoChange(servo_Pos)
  
  
  
  
  servoPos := 400 + 18 * servo_Pos       ' scale servo between .4 to 2.2 milliseconds
  
  
   
  PUB Servo | tInc,tHa,  tc, t
  
  
  ctra[30..26] := %00100                    ' Configure Counter A to NCO
  ctra[8..0]   := servoPin
  
  
  frqa := 1                                 ' add 1 to PHSA every clock cycle
  dira[servoPin]~~
  
  
   ' Set up cycle and high times
    tInc := clkfreq/1_000_000                ' clock cycles in 1 microsecond 
  
  
    servoPos := 1500                          ' 1500 microseconds = 90 degree position to start
  
  
    t    := cnt                              ' Mark counter time
  
  
   repeat                                    ' Repeat PWM signal
     tHa := tInc * servoPos                  ' update the pulse on time in clock cycles
     tC  := tInc * 20_000 + tHa              ' update the required interval in clock cycles        
     phsa := -tHa                            ' Set up the pulse
     t += tC                                 ' Calculate next cycle repeat
     waitcnt(t)                              ' Wait for next cycle
  
• kuroneko Posts: 3,623

  2011-11-13 16:20 edited 2011-11-13 16:20

  MikeS wrote: »

  If someone could look at my programs and give me a hint it would be greatly appreciated.Starting the Single Servo Spin in a new cog has got me confused and I suspect that is where the problem lies.

  Two things which stand out. One, the stack is too small. The MoveMotor method needs 7 longs in its current state (check the Stack Length object from the PropTool library). Which suggests that it interferes with other parts of the code. The second issue is that position is initially 0. After the motor cog is started it's at least a second before this variable is set to anything useful. This means the initial waitcnt in the MoveMotor method will be a waitcnt(cnt) which is effectively too late, i.e. you'll have to wait for a counter wrap-around (about a minute; this is just the way waitcnt works).
  
  So I'd suggest increasing the stack (e.g. stack[32], you can always make it smaller later). And before you start the motor cog, give position a meaningful value.
• MikeS Posts: 131

  2011-11-13 17:16 edited 2011-11-13 17:16

  Thank you for the reply. I did get the servo to run by itself.
• MikeS Posts: 131

  2011-11-13 17:21 edited 2011-11-13 17:21

  Chigasaki,
  Thank you for you suggestions. I will increase the stack and initialize the position to a value within the range given in the single servo spin program.
  Thanks,
  Mike
• MikeS Posts: 131

  2011-11-16 16:47 edited 2011-11-16 16:47

  Still not having success. I did increase the stack and initialized the servo position. Upon compile and download into RAM, the servo turns to the initialized position but the LCD never initialized and the switch apparently is not inputting to the Prop. If I comment out the cognew(MoveMotor(0),@Stack) line the LCD and switch work just fine. I guess Im going to have to try another servo object.
• kuroneko Posts: 3,623

  2011-11-16 16:57 edited 2011-11-16 16:57

  What if you start an empty method with the cognew? E.g.

  cognew(empty, @stack{0})
  
  PRI empty
  
    repeat
  

  does the LCD still refuse to initialise? Also, could you do another test and keep the motor in the cognew but do something simple afterwards, like blinking an LED? For clarity, could you also attach your current code (preferably archived)?
• MikeS Posts: 131

  2011-11-19 06:23 edited 2011-11-19 06:23

  Kuroneko,
  
  I "think" I may have found the problem. I noticed that if I did not plug the servo motor into the board that the LCD would go ahead and initialize. I increased the size of the power supply from 9.0v - 300ma to 9.0v - 500ma and the program appears to run now. There seems to still be a timing issue between the LCD displaying the switch position (doesn't always display) and the movement of the servo, but the servo is now moving in concert with the switch..
  I appreciate your reply and help, it encouraged me to pursue a solution to the problem
  
  .
  
  Thanks,
  MikeS

  zip

  zip

  5PositionSwitch_LCD_Servo - Archive [Date 2011.11.19 Time 08.02].zip

  18K

  5PositionSwitch_LCD_Servo - Archive [Date 2011.11.19 Time 08.02].zip 17.6K