Piclist Jal Bipolib.jal

-- 
-- Program: bipolar.jal library
--
-- Date: 14 July 2000
--
-- Author: G. Shearer
--         Vanderbilt University
--         Nashville, TN
--
-- Purpose: for driving both bipolar and unipolar stepper motors
-- uses Allegro UDN2998 dual H bridge

-- Copyright (C) 2000 G. Shearer
--
-- This library is free software; you can redistribute it and/or
-- modify it under the terms of the GNU Library General Public
-- License as published by the Free Software Foundation; either
-- version 2 of the License, or (at your option) any later version.
--
-- This library is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-- Library General Public License for more details.
--
-- You should have received a copy of the GNU Library General Public
-- License along with this library; if not, write to the
-- Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-- Boston, MA  02111-1307, USA.
--


procedure stepout ( byte in seq, byte in speed ) is
-- sends seq nibble to output

if seq == 0 then
port_a = 0b_0001
elsif seq == 1 then
port_a = 0b_1001
elsif seq == 2 then
port_a = 0b_0101
elsif seq == 3 then
port_a = 0b_0110
elsif seq == 4 then
port_a = 0b_0100
elsif seq == 5 then
port_a = 0b_1000
elsif seq == 6 then
port_a = 0b_0000
elsif seq == 7 then
port_a = 0b_0010
else
port_a = 0b_1010
end if
delay_1ms( speed )
end procedure

procedure fullforward ( byte in speed ) is
-- makes one full step in the forward direction

stepout( 1, speed )
stepout( 7, speed )
stepout( 5, speed )
stepout( 3, speed )
end procedure


procedure fullreverse ( byte in speed ) is
-- makes one full step in the reverse direction

stepout( 3, speed )
stepout( 5, speed )
stepout( 7, speed )
stepout( 1, speed )
end procedure

procedure halfstep ( bit in direction, byte in out seq, byte in speed ) is
-- makes one half step in the proper direction and remembers which half step

for 4 loop
if direction == true & seq < 7 then
	seq = seq + 1
elsif direction == true & seq == 7 then
	seq = 0
elsif direction == false & seq > 0 then
	seq = seq - 1
elsif direction == false & seq == 0 then
	seq = 7
end if
stepout ( seq, speed )
end loop
end procedure

procedure fullstep ( bit in direction, byte in speed ) is
-- detects forward/reverse direction and calls proper fullstep procedure

if direction == true then fullforward ( speed )
else fullreverse ( speed )
end if
end procedure