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+/*********************************************************************
+
+ mc146818.c
+
+ Implementation of the MC146818 chip
+
+ Real time clock chip with battery buffered ram (or CMOS)
+ Used in IBM PC/AT, several PC clones, Amstrad NC200, Apollo workstations
+
+ Nathan Woods (npwoods@mess.org)
+ Peter Trauner (peter.trauner@jk.uni-linz.ac.at)
+
+ PC CMOS info (based on info from Padgett Peterson):
+
+ Clock Related:
+ 0x00 Seconds (BCD 00-59, Hex 00-3B) Note: Bit 7 is read only
+ 0x01 Second Alarm (BCD 00-59, Hex 00-3B; "don't care" if C0-FF)
+ 0x02 Minutes (BCD 00-59, Hex 00-3B)
+ 0x03 Minute Alarm (BCD 00-59, Hex 00-3B; "don't care" if C0-FF))
+ 0x04 Hours (BCD 00-23, Hex 00-17 if 24 hr mode)
+ (BCD 01-12, Hex 01-0C if 12 hr am)
+ (BCD 81-92. Hex 81-8C if 12 hr pm)
+ 0x05 Hour Alarm (same as hours; "don't care" if C0-FF))
+ 0x06 Day of Week (01-07 Sunday=1)
+ 0x07 Date of Month (BCD 01-31, Hex 01-1F)
+ 0x08 Month (BCD 01-12, Hex 01-0C)
+ 0x09 Year (BCD 00-99, Hex 00-63)
+ 0x0B Status Register B (read/write)
+ Bit 7 - 1 enables cycle update, 0 disables
+ Bit 6 - 1 enables periodic interrupt
+ Bit 5 - 1 enables alarm interrupt
+ Bit 4 - 1 enables update-ended interrupt
+ Bit 3 - 1 enables square wave output
+ Bit 2 - Data Mode - 0: BCD, 1: Binary
+ Bit 1 - 24/12 hour selection - 1 enables 24 hour mode
+ Bit 0 - Daylight Savings Enable - 1 enables
+ 0x0C Status Register C (Read only)
+ Bit 7 - Interrupt request flag - 1 when any or all of bits 6-4 are
+ 1 and appropriate enables (Register B) are set to 1. Generates
+ IRQ 8 when triggered.
+ Bit 6 - Periodic Interrupt flag
+ Bit 5 - Alarm Interrupt flag
+ Bit 4 - Update-Ended Interrupt Flag
+ Bit 3-0 ???
+ 0x0D Status Register D (read only)
+ Bit 7 - Valid RAM - 1 indicates batery power good, 0 if dead or
+ disconnected.
+ Bit 6-0 ???
+
+ Non-clock related:
+ 0x0E (PS/2) Diagnostic Status Byte
+ Bit 7 - When set (1) indicates clock has lost power
+ Bit 6 - (1) indicates incorrect checksum
+ Bit 5 - (1) indicates that equipment configuration is incorrect
+ power-on check requires that atleast one floppy be installed
+ Bit 4 - (1) indicates error in memory size
+ Bit 3 - (1) indicates that controller or disk drive failed initialization
+ Bit 2 - (1) indicates that time is invalid
+ Bit 1 - (1) indicates installed adaptors do not match configuration
+ Bit 0 - (1) indicates a time-out while reading adaptor ID
+ 0x0E (AMSTRAD) 6 BYTEs time and date machine last used
+ 0x0F Reset Code (IBM PS/2 "Shutdown Status Byte")
+ 0x00-0x03 perform power-on reset
+ 0x04 INT 19h reboot
+ 0x05 flush keyboard and jump via 0040:0067
+ 0x06-0x07 reserved
+ 0x08 used by POST during protected-mode RAM test
+ 0x09 used for INT 15/87h (block move) support
+ 0x0A jump via 0040:0067
+ 0x0B-0xFF perform power-on reset
+
+*********************************************************************/
+
+#include "emu.h"
+#include "coreutil.h"
+#include "machine/mc146818.h"
+
+
+//**************************************************************************
+// DEBUGGING
+//**************************************************************************
+
+#define LOG_MC146818 0
+
+
+
+//**************************************************************************
+// MACROS
+//**************************************************************************
+
+#define USE_UTC 1
+
+#define HOURS_24 (m_data[0xb]&2)
+#define BCD_MODE !(m_data[0xb]&4) // book has other description!
+#define CENTURY m_data[100]
+#define YEAR m_data[9]
+#define MONTH m_data[8]
+#define DAY m_data[7]
+#define WEEK_DAY m_data[6]
+
+
+
+//**************************************************************************
+// LIVE DEVICE
+//**************************************************************************
+
+// device type definition
+const device_type MC146818 = &device_creator<mc146818_device>;
+
+//-------------------------------------------------
+// mc146818_device - constructor
+//-------------------------------------------------
+
+mc146818_device::mc146818_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock)
+ : device_t(mconfig, MC146818, "NVRAM", tag, owner, clock),
+ device_rtc_interface(mconfig, *this),
+ device_nvram_interface(mconfig, *this),
+ m_type(MC146818_STANDARD),
+ m_index(0),
+ m_eindex(0),
+ m_updated(false),
+ m_last_refresh(attotime::zero)
+{
+}
+
+
+//-------------------------------------------------
+// static_set_interface - configuration helper
+// to set the interface
+//-------------------------------------------------
+
+void mc146818_device::static_set_type(device_t &device, mc146818_type type)
+{
+ downcast<mc146818_device &>(device).m_type = type;
+}
+
+
+//-------------------------------------------------
+// device_start - device-specific startup
+//-------------------------------------------------
+
+void mc146818_device::device_start()
+{
+ m_last_refresh = machine().time();
+ m_clock_timer = timer_alloc(TIMER_CLOCK);
+ m_periodic_timer = timer_alloc(TIMER_PERIODIC);
+
+ memset(m_data, 0, sizeof(m_data));
+
+ if (m_type == MC146818_UTC) {
+ // hack: for apollo we increase the update frequency to stay in sync with real time
+ m_clock_timer->adjust(attotime::from_hz(2), 0, attotime::from_hz(2));
+ } else {
+ m_clock_timer->adjust(attotime::from_hz(1), 0, attotime::from_hz(1));
+ }
+
+ m_periodic_timer->adjust(attotime::never);
+ m_period = attotime::never;
+
+ set_base_datetime();
+
+ m_out_irq_func.resolve(m_out_irq_cb, *this);
+}
+
+//-------------------------------------------------
+// device_config_complete - perform any
+// operations now that the configuration is
+// complete
+//-------------------------------------------------
+
+void mc146818_device::device_config_complete()
+{
+ // inherit a copy of the static data
+ const mc146818_interface *intf = reinterpret_cast<const mc146818_interface *>(static_config());
+ if (intf != NULL)
+ *static_cast<mc146818_interface *>(this) = *intf;
+
+ // or initialize to defaults if none provided
+ else
+ {
+ memset(&m_out_irq_cb, 0, sizeof(m_out_irq_cb));
+ }
+}
+
+//-------------------------------------------------
+// device_timer - handler timer events
+//-------------------------------------------------
+
+void mc146818_device::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr)
+{
+ int year/*, month*/;
+
+ if (id == TIMER_PERIODIC) {
+ m_data[0x0c] |= 0xc0;
+ if (!m_out_irq_func.isnull()) m_out_irq_func(CLEAR_LINE);
+ return;
+ }
+
+ if (BCD_MODE)
+ {
+ m_data[0]=bcd_adjust(m_data[0]+1);
+ if (m_data[0]>=0x60)
+ {
+ m_data[0]=0;
+ m_data[2]=bcd_adjust(m_data[2]+1);
+ if (m_data[2]>=0x60)
+ {
+ m_data[2]=0;
+ m_data[4]=bcd_adjust(m_data[4]+1);
+ // different handling of hours
+ if (m_data[4]>=0x24)
+ {
+ m_data[4]=0;
+ WEEK_DAY=bcd_adjust(WEEK_DAY+1)%7;
+ DAY=bcd_adjust(DAY+1);
+ //month=bcd_2_dec(MONTH);
+ year=bcd_2_dec(YEAR);
+ if (m_type!=MC146818_IGNORE_CENTURY) year+=bcd_2_dec(CENTURY)*100;
+ else year+=2000; // save for julian_days_in_month calculation
+ DAY=bcd_adjust(DAY+1);
+ if (DAY>gregorian_days_in_month(MONTH, year))
+ {
+ DAY=1;
+ MONTH=bcd_adjust(MONTH+1);
+ if (MONTH>0x12)
+ {
+ MONTH=1;
+ YEAR=year=bcd_adjust(YEAR+1);
+ if (m_type!=MC146818_IGNORE_CENTURY)
+ {
+ if (year>=0x100)
+ {
+ CENTURY=bcd_adjust(CENTURY+1);
+ }
+ }
+ }
+ }
+ }
+ }
+ }
+ }
+ else
+ {
+ m_data[0]=m_data[0]+1;
+ if (m_data[0]>=60)
+ {
+ m_data[0]=0;
+ m_data[2]=m_data[2]+1;
+ if (m_data[2]>=60) {
+ m_data[2]=0;
+ m_data[4]=m_data[4]+1;
+ // different handling of hours //?
+ if (m_data[4]>=24) {
+ m_data[4]=0;
+ WEEK_DAY=(WEEK_DAY+1)%7;
+ year=YEAR;
+ if (m_type!=MC146818_IGNORE_CENTURY) year+=CENTURY*100;
+ else year+=2000; // save for julian_days_in_month calculation
+ if (++DAY>gregorian_days_in_month(MONTH, year)) {
+ DAY=1;
+ if (++MONTH>12) {
+ MONTH=1;
+ YEAR++;
+ if (m_type!=MC146818_IGNORE_CENTURY) {
+ if (YEAR>=100) { CENTURY++;YEAR=0; }
+ } else {
+ YEAR%=100;
+ }
+ }
+ }
+ }
+ }
+ }
+ }
+
+ if (m_data[1] == m_data[0] && //
+ m_data[3] == m_data[2] && //
+ m_data[5] == m_data[4]) {
+ // set the alarm interrupt flag AF
+ m_data[0x0c] |= 0x20;
+ } else {
+ // clear the alarm interrupt flag AF
+ m_data[0x0c] &= ~0x20;
+ if ((m_data[0x0c] & 0x70) == 0) {
+ // clear IRQF
+ m_data[0x0c] &= ~0x80;
+ }
+ }
+
+ // set the update-ended interrupt Flag UF
+ m_data[0x0c] |= 0x10;
+
+ // set the interrupt request flag IRQF
+ // FIXME: should throw IRQ line as well
+ if ((m_data[0x0b] & m_data[0x0c] & 0x30) != 0) {
+ m_data[0x0c] |= 0x80;
+ }
+
+ // IRQ line is active low
+ if (!m_out_irq_func.isnull()) m_out_irq_func((m_data[0x0c] & 0x80) ? CLEAR_LINE : ASSERT_LINE);
+
+ m_updated = true; /* clock has been updated */
+ m_last_refresh = machine().time();
+}
+
+
+//-------------------------------------------------
+// rtc_set_time - called to initialize the RTC to
+// a known state
+//-------------------------------------------------
+
+void mc146818_device::rtc_set_time(int year, int month, int day, int day_of_week, int hour, int minute, int second)
+{
+ YEAR = year;
+ MONTH = month;
+ DAY = day;
+ WEEK_DAY = day_of_week;
+ m_data[4] = hour;
+ m_data[2] = minute;
+ m_data[0] = second;
+}
+
+
+//-------------------------------------------------
+// nvram_default - called to initialize NVRAM to
+// its default state
+//-------------------------------------------------
+
+void mc146818_device::nvram_default()
+{
+ set_base_datetime();
+}
+
+
+//-------------------------------------------------
+// nvram_read - called to read NVRAM from the
+// .nv file
+//-------------------------------------------------
+
+void mc146818_device::nvram_read(emu_file &file)
+{
+ file.read(m_data, sizeof(m_data));
+ set_base_datetime();
+}
+
+
+//-------------------------------------------------
+// nvram_write - called to write NVRAM to the
+// .nv file
+//-------------------------------------------------
+
+void mc146818_device::nvram_write(emu_file &file)
+{
+ file.write(m_data, sizeof(m_data));
+}
+
+
+//-------------------------------------------------
+// dec_2_local - convert from decimal to BCD if
+// necessary
+//-------------------------------------------------
+
+inline int mc146818_device::dec_2_local(int a)
+{
+ return BCD_MODE ? dec_2_bcd(a) : a;
+}
+
+
+//-------------------------------------------------
+// dec_2_local - convert from decimal to BCD if
+// necessary
+//-------------------------------------------------
+
+void mc146818_device::set_base_datetime()
+{
+ system_time systime;
+ system_time::full_time current_time;
+
+ machine().base_datetime(systime);
+
+ current_time = (m_type == MC146818_UTC) ? systime.utc_time: systime.local_time;
+
+// logerror("mc146818_set_base_datetime %02d/%02d/%02d %02d:%02d:%02d\n",
+// current_time.year % 100, current_time.month + 1, current_time.mday,
+// current_time.hour,current_time.minute, current_time.second);
+
+ if (HOURS_24 || (current_time.hour < 12))
+ m_data[4] = dec_2_local(current_time.hour);
+ else
+ m_data[4] = dec_2_local(current_time.hour - 12) | 0x80;
+
+ if (m_type != MC146818_IGNORE_CENTURY)
+ CENTURY = dec_2_local(current_time.year /100);
+
+ m_data[0] = dec_2_local(current_time.second);
+ m_data[2] = dec_2_local(current_time.minute);
+ DAY = dec_2_local(current_time.mday);
+ MONTH = dec_2_local(current_time.month + 1);
+ YEAR = dec_2_local(current_time.year % 100);
+
+ WEEK_DAY = current_time.weekday;
+ if (current_time.is_dst)
+ m_data[0xb] |= 1;
+ else
+ m_data[0xb] &= ~1;
+}
+
+
+//-------------------------------------------------
+// read - I/O handler for reading
+//-------------------------------------------------
+
+READ8_MEMBER( mc146818_device::read )
+{
+ UINT8 data = 0;
+ switch (offset) {
+ case 0:
+ data = m_index;
+ break;
+
+ case 1:
+ switch (m_index % MC146818_DATA_SIZE) {
+ case 0xa:
+ data = m_data[m_index % MC146818_DATA_SIZE];
+ if ((space.machine().time() - m_last_refresh) < attotime::from_hz(32768))
+ data |= 0x80;
+#if 0
+ /* for pc1512 bios realtime clock test */
+ m_data[m_index % MC146818_DATA_SIZE] ^= 0x80; /* 0x80 update in progress */
+#endif
+ break;
+
+ case 0xc:
+// if(m_updated) /* the clock has been updated */
+// data = 0x10;
+// else
+// data = 0x00;
+ // the unused bits b0 ... b3 are always read as 0
+ data = m_data[m_index % MC146818_DATA_SIZE] & 0xf0;
+ // read 0x0c will clear all IRQ flags in register 0x0c
+ m_data[m_index % MC146818_DATA_SIZE] &= 0x0f;
+ if (!m_out_irq_func.isnull()) m_out_irq_func(ASSERT_LINE);
+ break;
+ case 0xd:
+ /* battery ok */
+ data = m_data[m_index % MC146818_DATA_SIZE] | 0x80;
+ break;
+
+ default:
+ data = m_data[m_index % MC146818_DATA_SIZE];
+ break;
+ }
+ break;
+ }
+
+ if (LOG_MC146818)
+ logerror("mc146818_port_r(): index=0x%02x data=0x%02x\n", m_index, data);
+ return data;
+}
+
+
+//-------------------------------------------------
+// write - I/O handler for writing
+//-------------------------------------------------
+
+WRITE8_MEMBER( mc146818_device::write )
+{
+ attotime rate;
+ if (LOG_MC146818)
+ logerror("mc146818_port_w(): index=0x%02x data=0x%02x\n", m_index, data);
+
+ switch (offset) {
+ case 0:
+ m_index = data;
+ break;
+
+ case 1:
+ switch(m_index % MC146818_DATA_SIZE)
+ {
+ case 0x0a:
+ // fixme: allow different time base
+ data &= 0x0f;
+ if (m_data[0x0b] & 0x40) {
+ if (data > 2)
+ m_period = attotime::from_hz(32768 >> (data - 1));
+ else if (data > 0)
+ m_period = attotime::from_hz(32768 >> (data + 6));
+ else m_period = attotime::never;
+ rate = attotime::zero;
+ } else rate = attotime::never;
+ m_periodic_timer->adjust(rate, 0, m_period);
+ data |= m_data[m_index % MC146818_DATA_SIZE] & 0xf0;
+ m_data[m_index % MC146818_DATA_SIZE] = data;
+ break;
+ case 0x0b:
+ if(data & 0x80)
+ m_updated = false;
+ // this probably isn't right but otherwise
+ // you'll be making a lot of unnecessary callbacks
+ if (data & 0x40)
+ m_periodic_timer->adjust(attotime::zero, 0, m_period);
+ else
+ m_periodic_timer->adjust(attotime::never);
+ m_data[m_index % MC146818_DATA_SIZE] = data;
+ break;
+ case 0x0c:
+ // register 0x0c is readonly
+ break;
+ default:
+ m_data[m_index % MC146818_DATA_SIZE] = data;
+ }
+ break;
+ }
+}