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ds.h revision 1.2 
      1 /*	$NetBSD: ds.h,v 1.2 1999/02/16 22:46:57 is Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1999 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Ignatios Souvatzis.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *        This product includes software developed by the NetBSD
     21  *        Foundation, Inc. and its contributors.
     22  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  *    contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  * POSSIBILITY OF SUCH DAMAGE.
     37  */
     38 
     39 /*
     40  * Definitions for access to Dallas Semiconductor chips which attach to
     41  * the same 1-wire bus as the DS2404 RTC.
     42  */
     43 
     44 #ifndef DALLAS_SEMI_CHIPS_H
     45 #define DALLAS_SEMI_CHIPS_H
     46 
     47 /* Family codes (low byte of the ROM) */
     48 
     49 #define DS_FAMILY_2404	0x04	/* DS2404 Econoram Time Chip */
     50 
     51 /*
     52  * ROM access codes. These are only available from the 1-wire bus, and one
     53  * of them MUST be used before a memory access code is called. If you want
     54  * to detect which devices are on the bus, you have to issue the ROM search
     55  * function (see data sheet).
     56  * If only one device is on the BUS, and you don't want any ROM function,
     57  * issue the SKIP function.
     58  * READ ROM works only if only one device is on the bus.
     59  */
     60 
     61 #define DS_ROM_MATCH		0x55	/* 55 8-bytes-of-ROM-to-select */
     62 #define DS_ROM_SEARCH		0xf0	/* see data sheet */
     63 #define DS_ROM_SKIP		0xCC	/* don't do ROM function */
     64 #define DS_ROM_READ		0x33	/* 33 -> 8 bytes of ROM */
     65 
     66 /*
     67  * Memory access codes. These are available from the 1- or 3-wire bus, and
     68  * but you must use one of the ROM access codes first, if using the 1-wire
     69  * bus.
     70  *
     71  * You can read from any starting address up to the end of the chip, or
     72  * abort the read with a reset pulse.
     73  * You first write 2-32 bytes beginning some address to the scratchpad.
     74  * Starting address and final byte stream length are remembered by the
     75  * chip. After reading data and address/length back from the scratchpad,
     76  * and verifying the information, you can issue the copy scratchpad command
     77  * to copy the written parts of the scratchpad to the corresponding parts
     78  * of the implied (in the address) memory page.
     79  */
     80 
     81 #define DS_MEM_WRITE_SCRATCH	0x0f	/* 0F low-ads high-ads data ... */
     82 #define DS_MEM_READ_SCRATCH	0xaa	/* AA -> low-ads high-ads end-ofs
     83 					 * data ... */
     84 #define DS_MEM_COPY_SCRATCH	0x55	/* 55 low-ads high-ads end-ofs */
     85 #define DS_MEM_READ_MEMORY	0xf0	/* F0 low-ads high-ads -> data ...*/
     86 
     87 /*
     88  * Hardware handle for access functions
     89  */
     90 
     91 struct ds_handle {
     92 	int (*ds_read_bit) __P((void *));
     93 	void (*ds_write_bit) __P((void *, int));
     94 	void (*ds_reset) __P((void *));
     95 	void *ds_hw_handle;
     96 };
     97 
     98 /*
     99  * Functions for access to Dallas Semiconductor chips which attach to
    100  * the same 1-wire bus as the DS2404 RTC.
    101  */
    102 
    103 static u_int8_t ds_read_byte __P((struct ds_handle *));
    104 static void ds_write_byte __P((struct ds_handle *, unsigned int));
    105 
    106 static inline u_int8_t
    107 ds_read_byte(dsh)
    108 	struct ds_handle *dsh;
    109 {
    110 	u_int8_t buf;
    111 	int i;
    112 
    113 	for (i=buf=0; i<8; ++i)
    114 		buf |= (dsh->ds_read_bit)(dsh->ds_hw_handle) << i;
    115 
    116 	return buf;
    117 }
    118 
    119 static inline void
    120 ds_write_byte(dsh, b)
    121 	struct ds_handle *dsh;
    122 	unsigned int b;
    123 {
    124 	int i;
    125 
    126 	for (i=0; i<8; ++i) {
    127 		(dsh->ds_write_bit)(dsh->ds_hw_handle, b & 1);
    128 		b >>= 1;
    129 	}
    130 }
    131 
    132 #endif /* DALLAS_SEMI_CHIPS_H */
    133