124 lines
4.2 KiB
C
124 lines
4.2 KiB
C
/* $NetBSD: ds.h,v 1.10 2012/02/12 16:34:11 matt Exp $ */
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/*-
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* Copyright (c) 1997 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Ignatios Souvatzis.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Definitions for access to Dallas Semiconductor chips which attach to
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* the same 1-wire bus as the DS2404 RTC.
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*/
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#ifndef DALLAS_SEMI_CHIPS_H
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#define DALLAS_SEMI_CHIPS_H
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/* Family codes (low byte of the ROM) */
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#define DS_FAMILY_2401 0x01 /* DS2401 Silicon Serial Number */
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#define DS_FAMILY_2404 0x04 /* DS2404 Econoram Time Chip */
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/*
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* ROM access codes. These are only available from the 1-wire bus, and one
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* of them MUST be used before a memory access code is called. If you want
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* to detect which devices are on the bus, you have to issue the ROM search
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* function (see data sheet).
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* If only one device is on the BUS, and you don't want any ROM function,
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* issue the SKIP function.
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* READ ROM works only if only one device is on the bus.
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*/
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#define DS_ROM_MATCH 0x55 /* 55 8-bytes-of-ROM-to-select */
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#define DS_ROM_SEARCH 0xf0 /* see data sheet */
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#define DS_ROM_SKIP 0xCC /* don't do ROM function */
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#define DS_ROM_READ 0x33 /* 33 -> 8 bytes of ROM */
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/*
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* Memory access codes. These are available from the 1- or 3-wire bus, and
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* but you must use one of the ROM access codes first, if using the 1-wire
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* bus.
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*
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* You can read from any starting address up to the end of the chip, or
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* abort the read with a reset pulse.
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* You first write 2-32 bytes beginning some address to the scratchpad.
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* Starting address and final byte stream length are remembered by the
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* chip. After reading data and address/length back from the scratchpad,
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* and verifying the information, you can issue the copy scratchpad command
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* to copy the written parts of the scratchpad to the corresponding parts
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* of the implied (in the address) memory page.
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*/
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#define DS_MEM_WRITE_SCRATCH 0x0f /* 0F low-ads high-ads data ... */
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#define DS_MEM_READ_SCRATCH 0xaa /* AA -> low-ads high-ads end-ofs
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* data ... */
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#define DS_MEM_COPY_SCRATCH 0x55 /* 55 low-ads high-ads end-ofs */
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#define DS_MEM_READ_MEMORY 0xf0 /* F0 low-ads high-ads -> data ...*/
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/*
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* Hardware handle for access functions
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*/
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struct ds_handle {
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int (*ds_read_bit)(void *);
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void (*ds_write_bit)(void *, int);
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void (*ds_reset)(void *);
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void *ds_hw_handle;
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};
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/*
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* Functions for access to Dallas Semiconductor chips which attach to
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* the same 1-wire bus as the DS2404 RTC.
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*/
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static u_int8_t ds_read_byte(struct ds_handle *);
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static void ds_write_byte(struct ds_handle *, unsigned int);
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static __inline u_int8_t
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ds_read_byte(struct ds_handle *dsh)
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{
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u_int8_t buf;
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int i;
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for (i=buf=0; i<8; ++i)
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buf |= (dsh->ds_read_bit)(dsh->ds_hw_handle) << i;
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return buf;
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}
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static __inline void
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ds_write_byte(struct ds_handle *dsh, unsigned int b)
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{
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int i;
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for (i=0; i<8; ++i) {
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(dsh->ds_write_bit)(dsh->ds_hw_handle, b & 1);
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b >>= 1;
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}
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}
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#endif /* DALLAS_SEMI_CHIPS_H */
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