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 Robotics / NXT / 855
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Subject: 
RE: RotateMotorEx hangs
Newsgroups: 
lugnet.robotics.nxt
Date: 
Sun, 5 Aug 2007 12:00:47 GMT
Viewed: 
21281 times
  
"... Maybe I could check that the power level is not equal to zero as
well..."

Good idea.  Will be included in the coming release?

--Elizabeth

-----Original Message-----
From: news-gateway@lugnet.com [mailto:news-gateway@lugnet.com] On Behalf Of
John Hansen
Sent: Friday, August 03, 2007 3:26 PM
To: lugnet.robotics.nxt@lugnet.com
Subject: Re: RotateMotorEx hangs

In lugnet.robotics.nxt, Elizabeth Mabrey wrote:
This is actually the topic about interrupting RotateMotor(). I resend with • a
more appropriate topic.
--E

When you call RotateMotorXXX here is the code that is executed:

subroutine __RotateMotor0
  brtst EQ, __rotate_Done0, __rotate_angle0
  sign __rotate_thePower0, __rotate_angle0
  abs __rotate_theAngle0, __rotate_angle0
  mul __rotate_thePower0, __rotate_thePower0, __rotate_power0

  set __rotate_theUF0,
UF_UPDATE_TACHO_LIMIT+UF_UPDATE_SPEED+UF_UPDATE_MODE+UF_UPDATE_PID_VALUES
  brtst EQ, __rotate_NoSync0, __rotate_sync0
  set __rotate_theOM0, OUT_MODE_MOTORON+OUT_MODE_BRAKE+OUT_MODE_REGULATED
  set __rotate_theRM0, OUT_REGMODE_SYNC
  mov __rotate_theTurnPct0, __rotate_turnpct0
  brtst EQ, __rotate_Start0, __rotate_theTurnPct0
  add __rotate_theUF0, __rotate_theUF0, UF_UPDATE_RESET_BLOCK_COUNT
  jmp __rotate_Start0
__rotate_NoSync0:
  set __rotate_theOM0, OUT_MODE_MOTORON+OUT_MODE_BRAKE
  set __rotate_theRM0, OUT_REGMODE_IDLE
  set __rotate_theTurnPct0, 0
__rotate_Start0:
  set __rotate_theRS0, OUT_RUNSTATE_RUNNING
  setout __rotate_ports0, OutputMode, __rotate_theOM0, RegMode,
__rotate_theRM0,
TachoLimit, __rotate_theAngle0, RunState, __rotate_theRS0, RegPValue,
__rotate_theRVP0, RegIValue, __rotate_theRVI0, RegDValue, __rotate_theRVD0,
Power, __rotate_thePower0, TurnRatio, __rotate_turnpct0, UpdateFlags,
__rotate_theUF0

// Waits till angle reached
  index __rotate_firstPort0, __rotate_ports0, NA
__rotate_Running0:
  getout __rotate_rs0, __rotate_firstPort0, RunState
  brcmp EQ, __rotate_Running0, __rotate_rs0, OUT_RUNSTATE_RUNNING
  brtst EQ, __rotate_Reset0, __rotate_stop0
// Regulates for speed = 0
  set __rotate_theOM0, OUT_MODE_MOTORON+OUT_MODE_BRAKE+OUT_MODE_REGULATED
  set __rotate_theRM0, OUT_REGMODE_SPEED
  set __rotate_theUF0, UF_UPDATE_SPEED+UF_UPDATE_MODE
  setout __rotate_ports0, OutputMode, __rotate_theOM0, RegMode,
__rotate_theRM0,
RunState, __rotate_theRS0, Power, 0, UpdateFlags, __rotate_theUF0
// Verifies that motor doesn't rotate for 50ms, else loops
  getout __rotate_RotCount0, __rotate_firstPort0, RotationCount
__rotate_Stabilize0:
  mov __rotate_OldRotCount0, __rotate_RotCount0
  // wait loop
  gettick __rotate_now0
  add __rotate_then0, __rotate_now0, 50
__rotate_Waiting0:
  gettick __rotate_now0
  brcmp LTEQ, __rotate_Waiting0, __rotate_now0, __rotate_then0
  // check rotation
  getout __rotate_RotCount0, __rotate_firstPort0, RotationCount
  brcmp NEQ, __rotate_Stabilize0, __rotate_OldRotCount0, __rotate_RotCount0
  setout __rotate_ports0, RunState, OUT_RUNSTATE_IDLE, OutputMode,
OUT_MODE_COAST, UpdateFlags, UF_UPDATE_MODE
__rotate_Reset0:
  // maybe reset the block rotation count
  brtst EQ, __rotate_Done0, __rotate_theTurnPct0
  setout __rotate_ports0, UpdateFlags, UF_UPDATE_RESET_BLOCK_COUNT
__rotate_Done0:
  return
ends


As you can see there are some loops in here.  The first loop repeats while
RunState is OUT_RUNSTATE_RUNNING.  Unfortunately, Off (which brakes the
motors)
specifically sets the RunState to OUT_RUNSTATE_RUNNING with a power level of
zero (i.e., to stop and brake the motors).  In order to interrupt the loop
in
RotateMotor you will need to stop the motors without braking by using Coast
instead of Off.

You can brake after you coast if you want but for at least a little while
the
motors need to not be in the running runstate otherwise this loop will not
exit.
Perhaps it would be good to introduce some other mechanism for breaking out
of
this loop other than checking the RunState value.  Maybe I could check that
the
power level is not equal to zero as well.

John Hansen



Message has 1 Reply:
  Re: RotateMotorEx hangs
 
(...) You asked for it, you got it. :-) John Hansen (17 years ago, 5-Aug-07, to lugnet.robotics.nxt)

Message is in Reply To:
  Re: RotateMotorEx hangs
 
(...) When you call RotateMotorXXX here is the code that is executed: subroutine __RotateMotor0 brtst EQ, __rotate_Done0, __rotate_angle0 sign __rotate_thePower0, __rotate_angle0 abs __rotate_theAngle0, __rotate_angle0 mul __rotate_thePower0, (...) (17 years ago, 3-Aug-07, to lugnet.robotics.nxt)

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