3d stepper source

;=======================================================================
;TITLE:         stepper.src
;
;PURPOSE:       control up to 3 stepper motors to move in straight lines
;		in space. Take commands from a serial port.
;
;AUTHOR:        Danny Havenith
;	Copyright (c) 2006 Danny Havenith
; Use, modification and distribution is subject to the Boost Software
; License, Version 1.0. (See copy at 
; http://www.boost.org/LICENSE_1_0.txt)
;
; UART VP and associated subroutines:
; Copyright © [01/26/1999] Scenix Semiconductor, Inc. All rights reserved.
;
;REVISIONS:
;
;CONNECTIONS:
; ra.0-2 3 keyboard row outputs
; rb.1-3 3 keyboard column inputs for keyboard matrix
;     ra.0 is the row output for the 'emergency keys' 
;     (min, max, emergency stop) and is always enabled (low-active) when motors move
;     This pin is also connected to a 'busy'-led.
; ra.3 serial out
; rb.0 serial in
; rb.4-7 Z-axis stepper motor output
; rc.0-3 X-axis stepper motor output
; rc.4-7 Y-axis stepper motor output
;
;
;DETAILS:
; Contains 2 VPs: 1) stepper motor controller 2) serial in/out
;=======================================================================


;-------------------------- DEVICE DIRECTIVES --------------------------

		DEVICE		SX28,OSCHS1,TURBO
		DEVICE		STACKX, OPTIONX

		IRC_CAL		IRC_SLOW

		RESET		Initialize
;------------------------------ CONSTANTS ------------------------------

;------------------------------ --------- ------------------------------
; The following constants are meant to be changed to configure for 
; diverse hardware.

Frequency		EQU	4_000_000 ; clock frequency
BaudRate		EQU	9600 	  ; serial port baudrate
InterruptsPerBit 	EQU	3	; samples per serial bit
HalfStepsPerSecond 	EQU 	350     ; stepper motor half steps/sec

; uncomment the following EQU if using a MAX232, since we need to
; reverse the rs-232 signals while not using a MAX232
UsingMAX232	EQU 1		; we're using a max232 

;------------------------------ --------- ------------------------------
; some derived constants (derived from the ones above)
; These are not meant to be changed manually.
;
		; clock ticks per interrupt
InterruptPeriod	EQU	Frequency/(InterruptsPerBit * BaudRate) + 1
		; value to put in W to obtain the clock ticks per interrupt
		; formulated in this particular way to get rid of 'Literal 
		; truncated to 8 bits' warning
RetiwValue	EQU 	256-InterruptPeriod 
		; Interrupts per stepper motor step
StepperDelay	EQU	Frequency/(HalfStepsPerSecond*InterruptPeriod)

; number of interrupts to pass between detection of the start bit ("flank") and
; the middle of the first bit, plus one (see code for that 'plus one').
StartDelay	EQU InterruptsPerBit/2 + InterruptsPerBit + 1

		; port definitions
OutputXY	EQU	rc ; port C outputs the signals for X(0-3) and Y(4-7) 
OutputZ		EQU	rb ; port B outputs the signals for Z on bits(0-3)
KeyboardRows	EQU	ra ; port A serves keyboard rows (outputs, a.0-a.2)
KeyboardRow0	EQU	ra.0
KeyboardRow1	EQU	ra.1
KeyboardRow2	EQU	ra.2
KeyboardColumns EQU	rb ; port B serves keyboard columns (inputs b.1-b.3)
KeyboardCol0	EQU	rb.1
KeyboardCol1	EQU	rb.2
KeyboardCol2	EQU	rb.3
KeyboardMask	EQU	%00000111

SerialOut	EQU	ra.3 ; pins ra.3 and rb.0 are serial output and
SerialIn	EQU	rb.0 ; input respectively.

;------------------------------ VARIABLES ------------------------------
			ORG	$08
; 'global' bank, registers that can be accessed regardles of the current
; bank.
ErrorTreshold	DS 2	; Error treshold (for Bresenhams)
Step1		DS 2	; Step siz