'--------Title--------
'
' File......switch2.pbp 
' Started....6/4/05
' Microcontroller used:  Microchip Technology 16F88
'                        microchip.com
' PicBasic Pro Code: micro-Engineering Labs, Inc.
'                    melabs.com 

'--------Program Desciption-------

' Switch drives LED and servo  

'----------Related Lesson----------

' switch2.pbp is used in the lesson ACTIVE HIGH ACTIVE LOW at:
' http://www.cornerstonerobotics.org/curriculum/lessons_year2/erii19_active_high_active_low.pdf

'-----------Comments--------------

' WITH THE PIC16F88, MAKE SURE TO HAVE TWO SEPARATE +5VDC 
' POWER SUPPLIES FOR THE PIC AND THE SERVO.  ALSO
' HAVE A COMMON GROUND BETWEEN THE POWER SUPPLIES.
' We use one 9V battery and two 78L05 voltage regulators. 
' See discussion about voltage regulators at:
' http://cornerstonerobotics.org/curriculum/lessons_year2/erii3_diodes_power_supplies_voltage_reg.pdf

' Also, initialize the state of PORTB as LOW
' since that will set the correct polarity of the 
' PULSOUT statement.  See PULSOUT in PicBasic Pro
' Compiler manual by microEngineering Labs, Inc.
' Look around page 121 in the PicBasic Pro Compiler Manual

'-----------Connections-----------

'		16F88 Pin			Wiring
'		---------			---------- 
'       RA0					Momentary Switch
'  		RB2					Servo Control Wire (Futaba uses white)  
'		RB0					LED

'--------Revision History--------    
 
' 3/2/06  Added comments
' 1/14/08 Change MCU from 16F84A to 16F88
' 1/14/08 Add 16F88 oscillator initialization

'---------Variables---------

	c0		VAR		BYTE		' Byte for counter
	switch	VAR		PORTA.0		' Pin RA0 is assigned the name switch
                                ' using the VAR command.	
  		 
'---------Initialization--------

	TRISA = %11111111           ' All PORTA pins are setup as inputs.
                                ' This can also be written TRISA = 255
	TRISB = %11111010           ' Pins RB0 and RB2 are set as outputs,
                                ' all other PORTB pins are set as inputs
 
	PORTB = %00000000	        ' Sets all PORTB pins to LOW(0 volts)
		                        ' Make certain to include this
                                ' initialization for the servo output 
                                ' pin as it sets the proper polarity 
                                ' of pulses in the PULSOUT command.
                                
    OSCCON = $60                ' Sets the internal oscillator in the
                                ' 16F88 to 4 MHz
	
    ANSEL = %00000000           ' Changes analog bits to digital.
                                ' See table below.
                       
'    Analog Bit    Analog or Digital      PIC16F88 Pin
'   ------------  ------------------     --------------
'       AN0            Digital                RA0
'       AN1            Digital                RA1
'       AN2            Digital                RA2
'       AN3            Digital                RA3
'       AN4            Digital                RA4
'       AN5            Digital                RB5
'       AN6            Digital                RB6                            
                                             
'--------Main Code--------

start:	   	                ' start label
	   
IF switch = 0 Then          ' If the momentary switch is pressed, pin
	                        ' RA0 goes from HIGH(+5 vdc) to LOW(0 vdc).
                            ' The comparison is true and the 
                            ' THEN statement is executed.
                            ' If the switch is not pressed, the 
                            ' comparison is false and the ELSE
                            ' statement is executed.
    
    For c0 = 1 TO 10    	' Send left servo signal 10 times
    
    high 0                  ' LED connected to RB0 is turned on
	
	PulsOut 2,100		    ' Pulse Width:
                            ' Sends a pulse out on pin RB2 for 1.0 msec.
                            ' The period,(100), is multiplied by the 
                            ' increment for a 4 MHz oscillator(10 usec)
                            ' to get a pulse out time of 1.0 msec.
                            ' To get the full range of your
                            ' servo, you may have to decrease the period
                            ' to less than 100, being careful not to go too
                            ' low thereby forcing the servo to stop
                            ' mechanically against the internal 
                            ' mechanical stops.
	
	Pause 19			    ' Pulse Interval:
                            ' Wait 19 msec before sending next pulse
                        
	Next c0                 ' Goes to next value of c0   		
                  
Else                        ' If the momentary switch connected to RA0
                            ' is not pressed and RA0 remains HIGH(+5 vdc).
                            ' The comparison is false and
                            ' the ELSE statement is executed.
	    
    For c0 = 1 TO 10	    ' Send right servo signal 10 times
    
    low 0                   ' LED connected to RB0 is turned off
	
	PulsOut 2,200	     	' Pulse Width:
                            ' Sends a pulse out on pin B2 for 2.0 msec.
                            ' The period,(200), is multiplied by the 
                            ' increment for a 4 MHz oscillator(10 usec)
                            ' to get a pulse out time of 2.0 msec.
                            ' To get the full range of your
                            ' servo, you may have to increase the period
                            ' to more than 200, being careful not to go too
                            ' high thereby forcing the servo to stop
                            ' mechanically against the internal 
                            ' mechanical stops.
                            	
	Pause 18			    ' Pulse Interval:
                            ' Wait 18 msec before sending next pulse
                        
	Next c0                 ' Goes to next value of c0   
                                     
	endif                   ' End of IF..THEN statement
	 	
	GoTo start				' Loop to start label 
    
    end