151 lines
6.2 KiB
C
151 lines
6.2 KiB
C
/*-
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* SPDX-License-Identifier: MIT-CMU
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*
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* Copyright (c) 1995 Carnegie-Mellon University.
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* All rights reserved.
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*
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* Permission to use, copy, modify and distribute this software and
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* its documentation is hereby granted, provided that both the copyright
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* notice and this permission notice appear in all copies of the
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* software, derivative works or modified versions, and any portions
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* thereof, and that both notices appear in supporting documentation.
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*
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* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
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* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
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* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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*
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* Carnegie Mellon requests users of this software to return to
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*
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* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
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* School of Computer Science
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* Carnegie Mellon University
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* Pittsburgh PA 15213-3890
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*
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* any improvements or extensions that they make and grant Carnegie the
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* rights to redistribute these changes.
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*
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* $NetBSD: mc146818reg.h,v 1.9 2006/03/08 23:46:25 lukem Exp $
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*
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* $FreeBSD$
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*/
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/*
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* Definitions for the Motorola MC146818A Real Time Clock.
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* They also apply for the (compatible) Dallas Semiconductor DS1287A RTC.
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*
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* Though there are undoubtedly other (better) sources, this material was
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* culled from the DEC "KN121 System Module Programmer's Reference
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* Information."
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*
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* The MC146818A has 16 registers. The first 10 contain time-of-year
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* and alarm data. The rest contain various control and status bits.
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*
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* To read or write the registers, one writes the register number to
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* the RTC's control port, then either reads from or writes the new
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* data to the RTC's data port. Since the locations of these ports
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* and the method used to access them can be machine-dependent, the
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* low-level details of reading and writing the RTC's registers are
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* handled by machine-specific functions.
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*
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* The time-of-year and alarm data can be expressed in either binary
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* or BCD, and they are selected by a bit in register B.
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*
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* The "hour" time-of-year and alarm fields can either be expressed in
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* AM/PM format, or in 24-hour format. If AM/PM format is chosen, the
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* hour fields can have the values: 1-12 and 81-92 (the latter being
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* PM). If the 24-hour format is chosen, they can have the values
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* 0-24. The hour format is selectable by a bit in register B.
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* (XXX IS AM/PM MODE DESCRIPTION CORRECT?)
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*
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* It is assumed the if systems are going to use BCD (rather than
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* binary) mode, or AM/PM hour format, they'll do the appropriate
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* conversions in machine-dependent code. Also, if the clock is
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* switched between BCD and binary mode, or between AM/PM mode and
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* 24-hour mode, the time-of-day and alarm registers are NOT
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* automatically reset; they must be reprogrammed with correct values.
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*/
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/*
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* The registers, and the bits within each register.
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*/
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#define MC_SEC 0x0 /* Time of year: seconds (0-59) */
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#define MC_ASEC 0x1 /* Alarm: seconds */
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#define MC_MIN 0x2 /* Time of year: minutes (0-59) */
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#define MC_AMIN 0x3 /* Alarm: minutes */
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#define MC_HOUR 0x4 /* Time of year: hour (see above) */
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#define MC_AHOUR 0x5 /* Alarm: hour */
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#define MC_DOW 0x6 /* Time of year: day of week (1-7) */
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#define MC_DOM 0x7 /* Time of year: day of month (1-31) */
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#define MC_MONTH 0x8 /* Time of year: month (1-12) */
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#define MC_YEAR 0x9 /* Time of year: year in century (0-99) */
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#define MC_REGA 0xa /* Control register A */
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#define MC_REGA_RSMASK 0x0f /* Interrupt rate select mask (see below) */
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#define MC_REGA_DVMASK 0x70 /* Divisor select mask (see below) */
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#define MC_REGA_DV0 0x10 /* Divisor 0 */
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#define MC_REGA_DV1 0x20 /* Divisor 1 */
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#define MC_REGA_DV2 0x40 /* Divisor 2 */
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#define MC_REGA_UIP 0x80 /* Update in progress; read only. */
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#define MC_REGB 0xb /* Control register B */
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#define MC_REGB_DSE 0x01 /* Daylight Savings Enable */
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#define MC_REGB_24HR 0x02 /* 24-hour mode (AM/PM mode when clear) */
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#define MC_REGB_BINARY 0x04 /* Binary mode (BCD mode when clear) */
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#define MC_REGB_SQWE 0x08 /* Square Wave Enable */
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#define MC_REGB_UIE 0x10 /* Update End interrupt enable */
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#define MC_REGB_AIE 0x20 /* Alarm interrupt enable */
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#define MC_REGB_PIE 0x40 /* Periodic interrupt enable */
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#define MC_REGB_SET 0x80 /* Allow time to be set; stops updates */
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#define MC_REGC 0xc /* Control register C */
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/* MC_REGC_UNUSED 0x0f UNUSED */
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#define MC_REGC_UF 0x10 /* Update End interrupt flag */
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#define MC_REGC_AF 0x20 /* Alarm interrupt flag */
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#define MC_REGC_PF 0x40 /* Periodic interrupt flag */
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#define MC_REGC_IRQF 0x80 /* Interrupt request pending flag */
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#define MC_REGD 0xd /* Control register D */
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/* MC_REGD_UNUSED 0x7f UNUSED */
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#define MC_REGD_VRT 0x80 /* Valid RAM and Time bit */
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#define MC_NREGS 0xe /* 14 registers; CMOS follows */
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#define MC_NTODREGS 0xa /* 10 of those regs are for TOD and alarm */
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#define MC_NVRAM_START 0xe /* start of NVRAM: offset 14 */
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#define MC_NVRAM_SIZE 50 /* 50 bytes of NVRAM */
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/*
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* Periodic Interrupt Rate Select constants (Control register A)
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*/
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#define MC_RATE_NONE 0x0 /* No periodic interrupt */
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#define MC_RATE_1 0x1 /* 256 Hz if MC_BASE_32_KHz, else 32768 Hz */
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#define MC_RATE_2 0x2 /* 128 Hz if MC_BASE_32_KHz, else 16384 Hz */
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#define MC_RATE_8192_Hz 0x3 /* 122.070 us period */
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#define MC_RATE_4096_Hz 0x4 /* 244.141 us period */
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#define MC_RATE_2048_Hz 0x5 /* 488.281 us period */
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#define MC_RATE_1024_Hz 0x6 /* 976.562 us period */
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#define MC_RATE_512_Hz 0x7 /* 1.953125 ms period */
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#define MC_RATE_256_Hz 0x8 /* 3.90625 ms period */
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#define MC_RATE_128_Hz 0x9 /* 7.8125 ms period */
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#define MC_RATE_64_Hz 0xa /* 15.625 ms period */
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#define MC_RATE_32_Hz 0xb /* 31.25 ms period */
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#define MC_RATE_16_Hz 0xc /* 62.5 ms period */
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#define MC_RATE_8_Hz 0xd /* 125 ms period */
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#define MC_RATE_4_Hz 0xe /* 250 ms period */
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#define MC_RATE_2_Hz 0xf /* 500 ms period */
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/*
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* Time base (divisor select) constants (Control register A)
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*/
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#define MC_BASE_4_MHz 0x00 /* 4 MHz crystal */
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#define MC_BASE_1_MHz MC_REGA_DV0 /* 1 MHz crystal */
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#define MC_BASE_32_KHz MC_REGA_DV1 /* 32 KHz crystal */
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#define MC_BASE_NONE (MC_REGA_DV2 | MC_REGA_DV1) /* actually also resets */
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#define MC_BASE_RESET (MC_REGA_DV2 | MC_REGA_DV1 | MC_REGA_DV0)
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