bf4eb52624
git-svn-id: https://svn.salfter.gotdns.org/svn/a2bfc/trunk@146 1b90f75b-8b96-4784-87c0-14078182fce6
101 lines
1.9 KiB
ArmAsm
101 lines
1.9 KiB
ArmAsm
; cc65 1-Wire Library
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; Copyright (C) 2003-2007 Scott Alfter (scott@alfter.us)
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;
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; This program is free software; you can redistribute it and/or modify
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; it under the terms of the GNU General Public License as published by
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; the Free Software Foundation, version 2.
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;
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; This program is distributed in the hope that it will be useful,
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; but WITHOUT ANY WARRANTY; without even the implied warranty of
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; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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; GNU General Public License for more details.
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;
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; You should have received a copy of the GNU General Public License
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; along with this program; if not, write to the Free Software
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; Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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; system-independent 1-Wire routines
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.export _ow_writebit
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.export _ow_writebyte
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.export _ow_readbit
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.export _ow_readbyte
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.export _ow_reset
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.export _ow_wait
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.export _ow_mswait
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; provided by system-specific routines at link time
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.import _ow_send1_impl
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.import _ow_send0_impl
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.import _ow_read_impl
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.import _ow_reset_impl
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.import _ow_wait_impl
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.import _ow_mswait_impl
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.bss
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owtmp: .res 1
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.code
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; some system-specific routines can be passed through
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_ow_send1 := _ow_send1_impl
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_ow_send0 := _ow_send0_impl
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_ow_wait := _ow_wait_impl
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_ow_mswait := _ow_mswait_impl
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; reset bus: return 0 if 1-Wire devices present, 1 otherwise
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_ow_reset:
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jsr _ow_reset_impl
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ldx #0
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txa
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adc #0
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rts
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; read a bit from the 1-Wire bus
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_ow_readbit:
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jsr _ow_read_impl
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ldx #0
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txa
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adc #0
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rts
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; write a bit to the 1-Wire bus
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_ow_writebit:
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ror ;shift out of LSB
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bcs :+
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jmp _ow_send0
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: jmp _ow_send1
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; write a byte to the 1-Wire bus
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_ow_writebyte:
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sta owtmp
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ldx #8
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: ror owtmp ;LSB is written first
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bcs :+
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jsr _ow_send0
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clc
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bcc :++
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: jsr _ow_send1
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: dex
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bne :---
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rts
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; read a byte from the 1-Wire bus
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_ow_readbyte:
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ldx #8
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: jsr _ow_read_impl
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ror owtmp
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dex
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bne :-
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lda owtmp
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ldx #0
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rts
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