My orignal code tracked the valve as to if it was open or not. But I need to
know when the air cylinder reaches the end limit. When the slave sees this
limit switch it turns on the _done line. Then I tried simpler code as in
this "test" program and it still does not work. Here is my test code.

@ DEVICE  pic16F877, hs_osc, wdt_off, pwrt_off, bod_off,
lvp_off,cpd_off,wrt_off, protect_off

DEFINE OSC 20       '20 MHz crystal

' - - - -SETUP PORTA for OUTPUT- - - - - - -
ADCON1 = 7          ' Set PORTA and PORTE to digital
TRISA = %00000000   ' set PortA for all output
PortA = %00000000   ' turn all lines on PortA OFF

' - - - -SETUP PORTB for INPUT- - - -
TRISB = %01111111 ' sparein, trig, emer on PORTB to input
Main_done            var PORTB.0    ' Main Air Supply done line
Clamp_done         var PORTB.1    ' Clamp done line
Index_done           var PORTB.2    ' Index done line
Tilt_done               var PORTB.3    ' Tilt done line
TV1_done             var PORTB.4    ' Transverse1 done line
TV2_done             var PORTB.5    ' Transverse2 done line
Counter_done      var PORTB.6    ' Counter done line
'                   var PORTB.7    ' not used

' - - - -SETUP PORTC for OUTPUT- - - -
TRISC = %00000000     ' set PortC for all output
PortC = %00000000       ' turn off all portC
Main                  var PORTC.0    ' Main Air Supply Valve
Clamp               var PORTC.1    ' Clamp Valve
Index                 var PORTC.2    ' Index Valve
Tilt                     var PORTC.3    ' Tilt Valve
TV1                   var PORTC.4    ' Transverse1 Valve
TV2                   var PORTC.5    ' Transverse2 Valve
Counter             var PORTC.6    ' Subract from Mechanical Counter
'                          var PORTC.7    ' not used

' - - - -SETUP PORTD for OUTPUT - - - -
 TRISD = %11110000     ' set PortD for 4 output & 4 input
PortD = %00000000       ' turn off all portD

' - - - -SETUP PORTE for OUTPUT- - - -
TRISE = %00000111     ' set PortE for all input
PortE = %00000000       ' turn off all portE

'--------------------------------------------------------
' = = = = = = = = = =
' = TEST Program  =
' = = = = = = = = = =
test:     Main = 1                               'Master signals Slave to
turn ON
            While Main_done = 0          'Wait till Slave signals that its
done
            Wend

            Clamp = 1                               'Master signals Slave to
turn ON
            While Clamp_done = 0          'Wait till Slave signals that its
done
            Wend

            Index = 1                               'Master signals Slave to
turn ON
            While Index_done = 0          'Wait till Slave signals that its
done
            Wend

            Main = 0                               'Master signals Slave to
turn OFF
            While Main_done = 0          'Wait till Slave signals that its
done
            Wend

            Clamp = 0                               'Master signals Slave to
turn OFF
            While Clamp_done = 0          'Wait till Slave signals that its
done
            Wend

            Index = 0                               'Master signals Slave to
turn OFF
            While Index_done = 0          'Wait till Slave signals that its
done
            Wend

goto test

 = = = = = = = = = = = = = = = = = = = = = = = = =
 = = = = = = = = = = = = = = = = = = = = = = = = =
 = = = = = = = = = = = = = = = = = = = = = = = = =



----- Original Message -----
From: "Olin Lathrop" <olin_piclist@EMBEDINC.COM>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Monday, August 20, 2001 4:02 AM
Subject: Re: [PIC]: ===== >B to C


> > Sometimes when the master activates the slave, the slave may already be
in
> > that position and the _done line will already show high (finished),
never
> > showing (low)busy.  Here is a piece of the code that the Master uses to
> talk
> > to slave. Does this piece of code require that it sees the "low" first
> then
> > exits when it goes "high"?
>
> I haven't looked at your code, but it might be simpler to have a valve
> open/closed line instead of command busy/done line.  That way you not only
> know when the slave has finished a command, but you also always know what
> state the valves are in.  If the master ever commands a slave to open its
> valve and that valve is already open, then the slave will do nothing and
the
> master sees the command completing immediately.
>
>
> ********************************************************************
> Olin Lathrop, embedded systems consultant in Littleton Massachusetts
> (978) 742-9014, olin@embedinc.com, http://www.embedinc.com
>
> --
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>
>
>

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