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