1/* 2 * Copyright (c) 1995 Carnegie-Mellon University. 3 * All rights reserved. 4 * 5 * Permission to use, copy, modify and distribute this software and 6 * its documentation is hereby granted, provided that both the copyright 7 * notice and this permission notice appear in all copies of the 8 * software, derivative works or modified versions, and any portions --- 7 unchanged lines hidden (view full) --- 16 * 17 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 18 * School of Computer Science 19 * Carnegie Mellon University 20 * Pittsburgh PA 15213-3890 21 * 22 * any improvements or extensions that they make and grant Carnegie the 23 * rights to redistribute these changes. |
24 * 25 * from: NetBSD: mc146818reg.h,v 1.5 2003/11/02 11:07:45 wiz Exp 26 * 27 * $FreeBSD: head/sys/dev/mc146818/mc146818reg.h 137821 2004-11-17 16:37:25Z marius $ |
28 */ 29 30/* 31 * Definitions for the Motorola MC146818A Real Time Clock. |
32 * They also apply for the (compatible) Dallas Semiconductor DS1287A RTC. |
33 * 34 * Though there are undoubtedly other (better) sources, this material was 35 * culled from the DEC "KN121 System Module Programmer's Reference 36 * Information." 37 * 38 * The MC146818A has 16 registers. The first 10 contain time-of-year 39 * and alarm data. The rest contain various control and status bits. 40 * --- 97 unchanged lines hidden (view full) --- 138/* 139 * Time base (divisor select) constants (Control register A) 140 */ 141#define MC_BASE_4_MHz 0x00 /* 4MHz crystal */ 142#define MC_BASE_1_MHz 0x10 /* 1MHz crystal */ 143#define MC_BASE_32_KHz 0x20 /* 32KHz crystal */ 144#define MC_BASE_NONE 0x60 /* actually, both of these reset */ 145#define MC_BASE_RESET 0x70 |