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/* $OpenBSD: ds.h,v 1.2 2002/03/14 01:26:54 millert Exp $ */
/* $NetBSD: ds.h,v 1.1 1997/07/06 22:22:01 is Exp $ */
/*-
* Copyright (c) 1997 Ignatios Souvatzis. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the author nor the names of contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* Definitions for access to Dallas Semiconductor chips which attach to
* the same 1-wire bus as the DS2404 RTC.
*/
#ifndef DALLAS_SEMI_CHIPS_H
#define DALLAS_SEMI_CHIPS_H
/* Family codes (low byte of the ROM) */
#define DS_FAMILY_2404 0x04 /* DS2404 Econoram Time Chip */
/*
* ROM access codes. These are only available from the 1-wire bus, and one
* of them MUST be used before a memory access code is called. If you want
* to detect which devices are on the bus, you have to issue the ROM search
* function (see data sheet).
* If only one device is on the BUS, and you don't want any ROM function,
* issue the SKIP function.
* READ ROM works only if only one device is on the bus.
*/
#define DS_ROM_MATCH 0x55 /* 55 8-bytes-of-ROM-to-select */
#define DS_ROM_SEARCH 0xf0 /* see data sheet */
#define DS_ROM_SKIP 0xCC /* don't do ROM function */
#define DS_ROM_READ 0x33 /* 33 -> 8 bytes of ROM */
/*
* Memory access codes. These are available from the 1- or 3-wire bus, and
* but you must use one of the ROM access codes first, if using the 1-wire
* bus.
*
* You can read from any starting address up to the end of the chip, or
* abort the read with a reset pulse.
* You first write 2-32 bytes beginning some address to the scratchpad.
* Starting address and final byte stream length are remembered by the
* chip. After reading data and address/length back from the scratchpad,
* and verifying the information, you can issue the copy scratchpad command
* to copy the written parts of the scratchpad to the corresponding parts
* of the implied (in the address) memory page.
*/
#define DS_MEM_WRITE_SCRATCH 0x0f /* 0F low-ads high-ads data ... */
#define DS_MEM_READ_SCRATCH 0xaa /* AA -> low-ads high-ads end-ofs
* data ... */
#define DS_MEM_COPY_SCRATCH 0x55 /* 55 low-ads high-ads end-ofs */
#define DS_MEM_READ_MEMORY 0xf0 /* F0 low-ads high-ads -> data ...*/
/*
* Hardware handle for access functions
*/
struct ds_handle {
int (*ds_read_bit)(void *);
void (*ds_write_bit)(void *, int);
void (*ds_reset)(void *);
void *ds_hw_handle;
};
/*
* Functions for access to Dallas Semiconductor chips which attach to
* the same 1-wire bus as the DS2404 RTC.
*/
static __inline u_int8_t ds_read_byte(struct ds_handle *);
static __inline void ds_write_byte(struct ds_handle *, unsigned int);
static __inline u_int8_t
ds_read_byte(dsh)
struct ds_handle *dsh;
{
u_int8_t buf;
int i;
for (i = buf = 0; i < 8; ++i)
buf |= (dsh->ds_read_bit)(dsh->ds_hw_handle) << i;
return buf;
}
static __inline void
ds_write_byte(dsh, b)
struct ds_handle *dsh;
unsigned int b;
{
int i;
for (i = 0; i < 8; ++i) {
(dsh->ds_write_bit)(dsh->ds_hw_handle, b & 1);
b >>= 1;
}
}
#endif /* DALLAS_SEMI_CHIPS_H */
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