'  ###########  start  ###########
'  avr:tiny13
'  ###########   end   ###########
'
' ******************************************************************
' A program to test Stepper Motors with a motor Breakoutbox
' 2017-12-19 (c) Paolo Iocco
' ******************************************************************
'
' Circuit diagram
' ---------------
'   ATtiny 13/45/85 Pin map
'                           +--\/--+
'   +5V>--/100k/----Reset---|1°   8|---Vcc----------------<+5V
'               DIR (PB3)<--|2    7|<--TRIMMER (PB2/ADC1) SCK
        '       STEP(PB4)<--|3    6|   NC      PB1 MISO
'   GND>--------------GND---|4    5|-->LED     PB0 MOSI
'                           +------+
'
' -------------------------------------------------------------
' 9.6MHz:
' LFuse: 0x7A; HFuse: 0x1F;
' AVRDude: avrdude -B 10 -c USBasp -p attiny13 -U lfuse:w:0x7a:m -U hfuse:w:0x1f:m
'
' ******************************************************************

' Chip model
#chip tiny13, 9.6

' pins & direction
#define led       PORTB.0
#define direzione PORTB.3
#define passo     PORTB.4
#define trimmer   PORTB.2
dir led out
dir direzione out
dir passo out
dir trimmer in

' variables
dim valore as byte
dim counter as byte

'Startup routine
Startup:
valore=0
counter=0

'Main routine
Loop:
	valore=ReadAD(ADC1)
	' determinazione della posizione, calcolo della velocità e del senso di rotazione
	select case valore
		case <= 120
			SET direzione OFF
			counter=121-valore
		case >= 135
			SET direzione ON
			counter=valore-134
		case else
			SET passo OFF
			set direzione OFF
			counter=0
	end select

	if counter>0 then
		SET led ON
		pulseout passo, counter ms
		SET led OFF
		wait counter ms
	end if

'Jump back to the start of the program
goto Loop