'{$STAMP BS2SX}
'' 
'' Programmer:     Craig Stuart Sapp <craig@ccrma.stanford.edu>
'' Creation Date:  Sun 07-11-1999
'' Last Modified:  Tue 07-13-1999
'' Filename:       cout.bsx
'' Syntax:         Basic Stamp IIsx
''
'' Description:    This program sends out the MIDI note middle C
''                 once every second.  The note remains on for
''                 1/2 of a second, and then is turned off for
''                 1/2 of a second. 
''                 The MIDI note-on message is [$90, 60, 127], where
''                    $90 = 144 = MIDI note-on command
''                     60       = Middle C as a MIDI note number
''                    127       = attack velocity (very loud)
''                 The MIDI note-off message is [$90, 60, 0], where
''                    $90 = a MIDI note-on command unless velocity is 0
''                     60 = the MIDI key to turn off
''                      0 = attack velocity of zero (i.e., turn note off)
''		
''  The MIDI Output Circuit connected between 5v power and pin 8 is:
''     +5V to 220 Ohm to MIDI 2; MIDI 4 to 220 Ohm to a pin.
''

outpin     con     8    ' output pin on which to send MIDI data
baudmode   con    60    ' baude mode for serout: (2500000/31250)-20 msec
                        ' note that this value should be 12 for BS2.
                        ' Serial rate for MIDI is 31,250 data bits/sec.
outpause   con     0    ' pause time in units of 0.4 millisec between bytes
                        ' on the BS2, units are 1.0 millisec

' According to BASIC Stamp Programming Manual v1.9, page 208:
' "Unused pins that are not connected to circuitry should be set to output" 
' to minimize power consumption. 
' which is done here:
DIRS = %1111111111111111
' Don't set pins connected to input circuitry to be output, or you can
' damage the Basic Stamp.


top:
   serout outpin, baudmode, outpause, [$90, 60, 127]
   pause 493            
   serout outpin, baudmode, outpause, [$90, 60, 0]
   pause 492
   goto top:

' Note that the pause times of 493 and 492 are the values
' needed (found empirically) to get a total period of 
' 1000 milliseconds for the loop.  A three-byte MIDI message
' takes about 1 millisecond to send.