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Laserist1984
Registered Member

Date Joined Nov 2009
Total Posts : 6

Posted 11/3/2009 9:46 AM (GMT -8)

Hello Forum ,

I have little problem in how to start to make a delay to turn LED on .

I wrote this code

PUB start|n
dira[LED_CONTROL]~~ 'set LED control port to output

WaitCnt(OneSecond*5 + Cnt)

repeat
    repeat while ina[Y_INDEXPULSE]>0 ' wait for pulse
    outa[LASER_CONTROL]~~             ' turn LED on
    WaitCnt(MicroSecond * 260 + Cnt) ' LED on at first line of frame
    outa[LED_CONTROL]~                ' turn LED off

i will write the pseudo code what i want from this program to do:

repeat:- while ina[Y_INDEXPULSE]>0,turn LED on,wait 260micro, LED off: i't done by the code above

- while ina[Y_INDEXPULSE]>0,wait 8ms to turn LED on,wait 260micro, LED off.

- while ina[Y_INDEXPULSE]>0,wait 6ms to turn LED on,wait 260micro, LED off.

- while ina[Y_INDEXPULSE]>0,wait 5ms to turn LED on,wait 260micro, LED off.

-while ina[Y_INDEXPULSE]>0,wait 4ms to turn LED on,wait 260micro, LED off.

-while ina[Y_INDEXPULSE]>0,wait 7 ms to turn LED on,wait 260micro, LED off.

how i can make it in intelligent way and nice in Spin ?

I hope that i describe good :-)

Thank you in advance

MagIO2
Registered Member

Date Joined Mar 2009
Total Posts : 596

Posted 11/3/2009 10:21 AM (GMT -8)

First of all you should replace the while ina - loop with the waitpne or waitpeq statement. Waitpeq and waitpne have better response times than you selfmade wait and reduce power consumption.

Reason: The ina might be read just a short moment before the pulse arrives. Then the comparison and the next repeat statement will be executed before the next ina. Waitpeq and waitpne have an equivalent PASM instruction. So, an internal comparator constantly checks the ina-register. As long as the wait-condition is not true, the COG is in a halt state.

Is it ensured that the pulse of that pin ends before your switch on - wait - switch off sequence is finished? Otherwise your wait until might react twice on the same pulse.

For your variable wait-time:

1. use a counter variable to count from 0 to 5 - for example in a repeat loop.

2. define a DAT section "waittimes" for example, which contains 6 long values that you have to add to cnt in the waitcnt-statement

DAT

waittimes long 400, clkfreq*8/1000, clkfreq*6/1000, clkfreq*5/1000 ...

3. Use these values in the waitcnt like

waitcnt( long[@waittimes+counter] + cnt )

Hope that helps. If you have further problems, ask again.

MagIO2
Registered Member

Date Joined Mar 2009
Total Posts : 596

Posted 11/3/2009 12:02 PM (GMT -8)

That should do the job:

PUB start | count
dira[LED_CONTROL]~~ 'set LED control port to output
WaitCnt( clkfreq + Cnt)

  ' This makes it an endless loop, you have to decide if you want that
repeat
    ' here is the counter which simply loops through the timing list in the dat section.
    ' As we have 6 values in the list, we loop from 0 to 5
    repeat count from 0 to 5
      ' this replaces your repeat until, which checks the input-pin.
      ' As mentioned this only works fine if the pulse on Y_INDEXPULSE is shorter than the waittime and the
      ' 260 microseconds. If not simply add a waitpne with the same parameters. That makes sure that the input
      ' pin was low before waiting for high
      waitpeq( 1<<Y_INDEXPULSE, 1<<Y_INDEXPULSE, 0 )
      ' here we wait for the time found in the table at position "count"
      waitcnt( long[ @waittime+count ] + cnt )
      outa[LED_CONTROL]~~             ' turn LED on
      WaitCnt(MicroSecond * 260 + Cnt) ' LED on at first line of frame
      outa[LED_CONTROL]~                ' turn LED off

DAT
MicroSecond long 80

waittime long 400                    ' waittime + 0, this is close to the shortest time you can wait
         long 80_000_000 * 8 / 1000 ' waittime + 1
         long 80_000_000 * 6 / 1000  ' waittime + 2
         long 80_000_000 * 5 / 1000 ' waittime + 3
         long 80_000_000 * 4 / 1000 ' ....
         long 80_000_000 * 7 / 1000
         ' 80_000_000/1000 is equal to 1 ms if you run the prop with 80MHz.
         ' If not you have to change 80_000_000. The multiplication is done
         ' before because we don't want to loose digits due to integer-arithmetics

Laserist1984
Registered Member

Date Joined Nov 2009
Total Posts : 6

Posted 11/3/2009 12:07 PM (GMT -8)

Thank you alooot MagIo2 , i will try it and i will tell you about results .
Have a nice day

Laserist1984
Registered Member

Date Joined Nov 2009
Total Posts : 6

Posted 11/3/2009 4:13 PM (GMT -8)

it's seems something wrong happen , i am trying to make change in this code if i want to do: when the first time ina[Y_INDEXPULSE]>0 , LED will be ON 260 microsecond , LED off , after 10 millisecond LED is ON 260microsecond , LED off, after 10 millisecond LED is ON 260microsecond , LED off .....

PUB start
dira[LED_CONTROL]~~ 'set LED control port to output

WaitCnt( clkfreq + Cnt)

if ina[Y_INDEXPULSE]>0

      Repeat
      outa[LED_CONTROL]~~             ' turn LED on
      WaitCnt(MicroSecond * 260 + Cnt) ' LED on 260 microsecond
      outa[LED_CONTROL]~                ' turn LED off
      waitcnt( long[@waittime] + cnt )     ' wait 10 millisecond

DAT
MicroSecond long 80

waittime long 80_000_000 * 10 / 1_000 ' 80_000_000/1000 is equal to 1 ms

what can the problem from ?

thanks in advance.

Laserist1984
Registered Member

Date Joined Nov 2009
Total Posts : 6

Posted 11/4/2009 2:23 AM (GMT -8)

hello,
please can someone tell me where the problem in the code mentioned above?
thanks

MagIO2
Registered Member

Date Joined Mar 2009
Total Posts : 596

Posted 11/4/2009 3:02 AM (GMT -8)

PUB start
dira[LED_CONTROL]~~ 'set LED control port to output

WaitCnt( clkfreq + Cnt)

' if does not wait until pin is high, it just checks. And if statement is true, it executes the correctly indented code

~~if ina[Y_INDEXPULSE]>0~~

waitpeq( 1<<Y_INDEXPULSE, 1<<Y_INDEXPULSE, 0 )

' indentation ... only code correctly indented is repeated

repeat
      outa[LED_CONTROL]~~             ' turn LED on
      WaitCnt(MicroSecond * 260 + Cnt) ' LED on 260 microsecond
      outa[LED_CONTROL]~                ' turn LED off
      waitcnt( long[@waittime] + cnt )     ' wait 10 millisecond

DAT
MicroSecond long 80

waittime long 80_000_000 * 10 / 1_000 ' 80_000_000/1000 is equal to 1 ms

Please note: Indentation is very important in SPIN. It replaces characters marking blocks as known in other programming languages. ( in C { 'do something } is a block )

This will only wait for a pulse on Y_INDEXPULSE and then repeat forever. If you want it only to run if the input is high you need to change it a bit:

PUB start
dira[LED_CONTROL]~~ 'set LED control port to output

WaitCnt( clkfreq + Cnt)

repeat
waitpeq( 1<<Y_INDEXPULSE, 1<<Y_INDEXPULSE, 0 )

    repeat while ina[Y_INDEXPULSE]    ' the >0 only eats up runtime. Every number that is not 0 will keep the loop running
      outa[LED_CONTROL]~~             ' turn LED on
      WaitCnt(MicroSecond * 260 + Cnt) ' LED on 260 microsecond
      outa[LED_CONTROL]~                ' turn LED off
      waitcnt( long[@waittime] + cnt )     ' wait 10 millisecond

DAT
MicroSecond long 80

waittime long 80_000_000 * 10 / 1_000 ' 80_000_000/1000 is equal to 1 ms

mpark
Registered Member

Date Joined May 2007
Total Posts : 682

Posted 11/4/2009 4:54 AM (GMT -8)

MagIO2 said...

waitcnt( long[@waittime] + cnt ) ' wait 10 millisecond

Hey MagIO2, why not just

waitcnt( waittime + cnt ) ' wait 10 millisecond

?

Also, earlier you suggested
waitcnt( long[@waittimes+counter] + cnt )
but that won't work unless counter is a multiple of four. Just use
waitcnt( waittimes[counter] + cnt )

MagIO2
Registered Member

Date Joined Mar 2009
Total Posts : 596

Posted 11/4/2009 7:21 AM (GMT -8)

Hi mpark ...

thanks for the comments.

I simply did not recheck that waitcnt-line, so it missed the evolution.
About the long: These things happen if you don't test the code before posting. I'm guilty for that.

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