// license:BSD-3-Clause
// copyright-holders:R. Belmont
/**********************************************************************
mm58167.c - National Semiconductor MM58167 real-time clock emulation
TODO: standby interrupt
**********************************************************************/
#include "emu.h"
#include "mm58167.h"
#include "machine/timehelp.h"
//**************************************************************************
// LIVE DEVICE
//**************************************************************************
// device type definition
DEFINE_DEVICE_TYPE(MM58167, mm58167_device, "mm58167", "National Semiconductor MM58167 RTC")
// registers (0-7 are the live data, 8-f are the setting for the compare IRQ)
typedef enum
{
R_CNT_MILLISECONDS = 0, // 0 = milliseconds [0..9]
R_CNT_HUNDTENTHS, // 1 = hundreds and tenths of seconds [0..99]
R_CNT_SECONDS, // 2 = seconds [0..59]
R_CNT_MINUTES, // 3 = minutes [0..59]
R_CNT_HOURS, // 4 = hours [0..23]
R_CNT_DAYOFWEEK, // 5 = day of the week [1..7, Sunday = 1]
R_CNT_DAYOFMONTH, // 6 = day of the month [1..31; but Feb 29 = Mar 0]
R_CNT_MONTH, // 7 = month [1..12]
R_RAM_MILLISECONDS, // 8 = milliseconds
R_RAM_HUNDTENTHS, // 9 = hundreds and tenths of seconds
R_RAM_SECONDS, // a = seconds
R_RAM_MINUTES, // b = minutes
R_RAM_HOURS, // c = hours
R_RAM_DAYOFWEEK, // d = day of the week
R_RAM_DAYOFMONTH, // e = day of the month
R_RAM_MONTH, // f = month
R_CTL_IRQSTATUS, // 10 = IRQ status (b7 = compare, b6 = 10th sec, b5 = sec, b4 = min, b3 = hour, b2 = day, b1 = week, b0 = month)
R_CTL_IRQCONTROL, // 11 = IRQ control (same bit layout as status, but write here to enable/disable/clear)
R_CTL_RESETCOUNTERS, // 12 = reset counters
R_CTL_RESETRAM, // 13 = reset RAM
R_CTL_STATUS, // 14 = status bit
R_CTL_GOCMD, // 15 = GO Command
R_CTL_STANDBYIRQ, // 16 = standby IRQ
R_CTL_TESTMODE // 17 = test mode
} mm58167_regs_t;
//-------------------------------------------------
// mm58167_device - constructor
//-------------------------------------------------
mm58167_device::mm58167_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
: device_t(mconfig, MM58167, tag, owner, clock),
device_rtc_interface(mconfig, *this),
m_irq_w(*this)
{
}
//-------------------------------------------------
// device_start - device-specific startup
//-------------------------------------------------
void mm58167_device::device_start()
{
// allocate timers
m_clock_timer = timer_alloc(FUNC(mm58167_device::clock_tick), this);
m_clock_timer->adjust(attotime::from_hz(clock() / 32.768f), 0, attotime::from_hz(clock() / 32.768f));
// state saving
save_item(NAME(m_regs));
save_item(NAME(m_milliseconds));
save_item(NAME(m_comparator_state));
}
//-------------------------------------------------
// device_reset - device-specific reset
//-------------------------------------------------
void mm58167_device::device_reset()
{
m_regs[R_CTL_STATUS] = 0; // not busy
m_regs[R_CTL_IRQSTATUS] = 0;
m_regs[R_CTL_IRQCONTROL] = 0;
m_milliseconds = 0;
m_comparator_state = false;
}
//-------------------------------------------------
// clock_tick - advance the RTC's registers
//-------------------------------------------------
TIMER_CALLBACK_MEMBER(mm58167_device::clock_tick)
{
m_milliseconds++;
if (m_milliseconds >= 999)
{
int old_seconds = m_regs[R_CNT_SECONDS];
int old_minutes = m_regs[R_CNT_MINUTES];
int old_hours = m_regs[R_CNT_HOURS];
int old_dayofmonth = m_regs[R_CNT_DAYOFMONTH];
int old_dayofweek = m_regs[R_CNT_DAYOFWEEK];
int old_month = m_regs[R_CNT_MONTH];
advance_seconds();
m_milliseconds = 0;
if ((m_regs[R_CTL_IRQCONTROL] & 0x04) && m_regs[R_CNT_SECONDS] != old_seconds) set_irq(2); // every second
if ((m_regs[R_CTL_IRQCONTROL] & 0x08) && m_regs[R_CNT_MINUTES] != old_minutes) set_irq(3); // every minute
if ((m_regs[R_CTL_IRQCONTROL] & 0x10) && m_regs[R_CNT_HOURS] != old_hours) set_irq(4); // every hour
if ((m_regs[R_CTL_IRQCONTROL] & 0x20) && m_regs[R_CNT_DAYOFMONTH] != old_dayofmonth) set_irq(5); // every day
if ((m_regs[R_CTL_IRQCONTROL] & 0x40) && m_regs[R_CNT_DAYOFWEEK] < old_dayofweek) set_irq(6); // every week
if ((m_regs[R_CTL_IRQCONTROL] & 0x80) && m_regs[R_CNT_MONTH] != old_month) set_irq(7); // every month
}
m_regs[R_CNT_MILLISECONDS] = time_helper::make_bcd(m_milliseconds % 10);
m_regs[R_CNT_HUNDTENTHS] = time_helper::make_bcd(m_milliseconds / 10);
// 10Hz IRQ
if ((m_regs[R_CTL_IRQCONTROL] & 0x02) && (m_milliseconds % 100) == 0)
set_irq(1);
// comparator IRQ
bool new_state = true;
for (int i = R_CNT_MILLISECONDS; i <= R_CNT_MONTH; i++)
{
// nibbles that have the 2 MSB set always compares true
// Milliseconds use only the high nibble and Day of Week only the low nibble
if ((i != R_CNT_MILLISECONDS && (m_regs[i + 8] & 0x0c) != 0x0c && (m_regs[i + 8] & 0x0f) != (m_regs[i] & 0x0f)) ||
(i != R_CNT_DAYOFWEEK && (m_regs[i + 8] & 0xc0) != 0xc0 && (m_regs[i + 8] & 0xf0) != (m_regs[i] & 0xf0)))
{
new_state = false;
break;
}
}
if ((m_regs[R_CTL_IRQCONTROL] & 0x01) && !m_comparator_state && new_state) // positive-edge-triggered
set_irq(0);
m_comparator_state = new_state;
}
//-------------------------------------------------
// rtc_clock_updated -
//-------------------------------------------------
void mm58167_device::rtc_clock_updated(int year, int month, int day, int day_of_week, int hour, int minute, int second)
{
m_regs[R_CNT_SECONDS] = time_helper::make_bcd(second); // seconds (BCD)
m_regs[R_CNT_MINUTES] = time_helper::make_bcd(minute); // minutes (BCD)
m_regs[R_CNT_HOURS] = time_helper::make_bcd(hour); // hour (BCD)
m_regs[R_CNT_DAYOFWEEK] = time_helper::make_bcd(day_of_week); // day of the week (BCD)
m_regs[R_CNT_DAYOFMONTH] = time_helper::make_bcd(day); // day of the month (BCD)
m_regs[R_CNT_MONTH] = time_helper::make_bcd(month); // month (BCD)
}
void mm58167_device::set_irq(int bit)
{
m_regs[R_CTL_IRQSTATUS] |= (1 << bit);
m_irq_w(ASSERT_LINE);
}
void mm58167_device::update_rtc()
{
set_clock_register(RTC_SECOND, bcd_to_integer(m_regs[R_CNT_SECONDS]));
set_clock_register(RTC_MINUTE, bcd_to_integer(m_regs[R_CNT_MINUTES]));
set_clock_register(RTC_HOUR, bcd_to_integer(m_regs[R_CNT_HOURS]));
set_clock_register(RTC_DAY, bcd_to_integer(m_regs[R_CNT_DAYOFMONTH]));
set_clock_register(RTC_DAY_OF_WEEK, bcd_to_integer(m_regs[R_CNT_DAYOFWEEK]));
set_clock_register(RTC_MONTH, bcd_to_integer(m_regs[R_CNT_MONTH]));
m_milliseconds = (bcd_to_integer(m_regs[R_CNT_HUNDTENTHS]) * 10) + (bcd_to_integer(m_regs[R_CNT_MILLISECONDS] >> 4) % 10);
}
uint8_t mm58167_device::read(offs_t offset)
{
// printf("read reg %x = %02x\n", offset, m_regs[offset]);
if (offset == R_CTL_IRQSTATUS && !machine().side_effects_disabled())
{
// reading the IRQ status clears IRQ line and IRQ status
uint8_t data = m_regs[offset];
m_regs[R_CTL_IRQSTATUS] = 0;
m_irq_w(CLEAR_LINE);
return data;
}
return m_regs[offset];
}
void mm58167_device::write(offs_t offset, uint8_t data)
{
// printf("%02x to reg %x\n", data, offset);
if ((offset >= R_RAM_MILLISECONDS) && (offset != R_CTL_IRQSTATUS))
{
m_regs[offset] = data;
}
switch (offset)
{
case R_CNT_MILLISECONDS:
case R_CNT_HUNDTENTHS:
case R_CNT_SECONDS:
case R_CNT_MINUTES:
case R_CNT_HOURS:
case R_CNT_DAYOFWEEK:
case R_CNT_DAYOFMONTH:
case R_CNT_MONTH:
m_regs[offset] = data;
update_rtc();
break;
// any write to this starts at the current time and zero milliseconds
case R_CTL_GOCMD:
m_milliseconds = 0;
break;
case R_CTL_RESETCOUNTERS:
if (data == 0xff)
{
m_regs[R_CNT_MILLISECONDS] = 0;
m_regs[R_CNT_HUNDTENTHS] = 0;
m_regs[R_CNT_SECONDS] = 0;
m_regs[R_CNT_MINUTES] = 0;
m_regs[R_CNT_HOURS] = 0;
m_regs[R_CNT_DAYOFWEEK] = 1;
m_regs[R_CNT_DAYOFMONTH] = 1;
m_regs[R_CNT_MONTH] = 1;
update_rtc();
}
break;
case R_CTL_RESETRAM:
if (data == 0xff)
{
for (int i = R_RAM_MILLISECONDS; i < R_CTL_IRQSTATUS; i++)
{
m_regs[i] = 0;
}
}
break;
case R_CTL_IRQCONTROL:
m_regs[R_CTL_IRQCONTROL]=data;
break;
}
}