1 /* $OpenBSD: ds.h,v 1.2 2002/03/14 01:26:54 millert Exp $ */
2 /* $NetBSD: ds.h,v 1.1 1997/07/06 22:22:01 is Exp $ */
3
4 /*-
5 * Copyright (c) 1997 Ignatios Souvatzis. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the author nor the names of contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 /*
33 * Definitions for access to Dallas Semiconductor chips which attach to
34 * the same 1-wire bus as the DS2404 RTC.
35 */
36
37 #ifndef DALLAS_SEMI_CHIPS_H
38 #define DALLAS_SEMI_CHIPS_H
39
40 /* Family codes (low byte of the ROM) */
41
42 #define DS_FAMILY_2404 0x04 /* DS2404 Econoram Time Chip */
43
44 /*
45 * ROM access codes. These are only available from the 1-wire bus, and one
46 * of them MUST be used before a memory access code is called. If you want
47 * to detect which devices are on the bus, you have to issue the ROM search
48 * function (see data sheet).
49 * If only one device is on the BUS, and you don't want any ROM function,
50 * issue the SKIP function.
51 * READ ROM works only if only one device is on the bus.
52 */
53
54 #define DS_ROM_MATCH 0x55 /* 55 8-bytes-of-ROM-to-select */
55 #define DS_ROM_SEARCH 0xf0 /* see data sheet */
56 #define DS_ROM_SKIP 0xCC /* don't do ROM function */
57 #define DS_ROM_READ 0x33 /* 33 -> 8 bytes of ROM */
58
59 /*
60 * Memory access codes. These are available from the 1- or 3-wire bus, and
61 * but you must use one of the ROM access codes first, if using the 1-wire
62 * bus.
63 *
64 * You can read from any starting address up to the end of the chip, or
65 * abort the read with a reset pulse.
66 * You first write 2-32 bytes beginning some address to the scratchpad.
67 * Starting address and final byte stream length are remembered by the
68 * chip. After reading data and address/length back from the scratchpad,
69 * and verifying the information, you can issue the copy scratchpad command
70 * to copy the written parts of the scratchpad to the corresponding parts
71 * of the implied (in the address) memory page.
72 */
73
74 #define DS_MEM_WRITE_SCRATCH 0x0f /* 0F low-ads high-ads data ... */
75 #define DS_MEM_READ_SCRATCH 0xaa /* AA -> low-ads high-ads end-ofs
76 * data ... */
77 #define DS_MEM_COPY_SCRATCH 0x55 /* 55 low-ads high-ads end-ofs */
78 #define DS_MEM_READ_MEMORY 0xf0 /* F0 low-ads high-ads -> data ...*/
79
80 /*
81 * Hardware handle for access functions
82 */
83
84 struct ds_handle {
85 int (*ds_read_bit)(void *);
86 void (*ds_write_bit)(void *, int);
87 void (*ds_reset)(void *);
88 void *ds_hw_handle;
89 };
90
91 /*
92 * Functions for access to Dallas Semiconductor chips which attach to
93 * the same 1-wire bus as the DS2404 RTC.
94 */
95
96 static __inline u_int8_t ds_read_byte(struct ds_handle *);
97 static __inline void ds_write_byte(struct ds_handle *, unsigned int);
98
99 static __inline u_int8_t
ds_read_byte(dsh)100 ds_read_byte(dsh)
101 struct ds_handle *dsh;
102 {
103 u_int8_t buf;
104 int i;
105
106 for (i = buf = 0; i < 8; ++i)
107 buf |= (dsh->ds_read_bit)(dsh->ds_hw_handle) << i;
108
109 return buf;
110 }
111
112 static __inline void
ds_write_byte(dsh,b)113 ds_write_byte(dsh, b)
114 struct ds_handle *dsh;
115 unsigned int b;
116 {
117 int i;
118
119 for (i = 0; i < 8; ++i) {
120 (dsh->ds_write_bit)(dsh->ds_hw_handle, b & 1);
121 b >>= 1;
122 }
123 }
124
125 #endif /* DALLAS_SEMI_CHIPS_H */
126