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mc146818: improve update in progress handling

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This commit is contained in:
Patrick Mackinlay 2021-03-25 13:21:29 +07:00
parent df10451c06
commit 0f205b5db4
2 changed files with 51 additions and 16 deletions
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54
src/devices/machine/mc146818.cpp
View File

@ -22,6 +22,7 @@
// device type definition
DEFINE_DEVICE_TYPE(MC146818, mc146818_device, "mc146818", "MC146818 RTC")
DEFINE_DEVICE_TYPE(DS1287, ds1287_device, "ds1287", "DS1287 RTC")
//-------------------------------------------------
// mc146818_device - constructor
@ -29,6 +30,21 @@ DEFINE_DEVICE_TYPE(MC146818, mc146818_device, "mc146818", "MC146818 RTC")
mc146818_device::mc146818_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
: mc146818_device(mconfig, MC146818, tag, owner, clock)
{
switch (clock)
{
case 4'194'304:
case 1'048'576:
m_tuc = 248;
break;
case 32'768:
m_tuc = 1984;
break;
}
}
ds1287_device::ds1287_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
: mc146818_device(mconfig, DS1287, tag, owner, clock)
{
}
@ -37,7 +53,7 @@ mc146818_device::mc146818_device(const machine_config &mconfig, device_type type
device_nvram_interface(mconfig, *this),
m_region(*this, DEVICE_SELF),
m_index(0),
m_last_refresh(attotime::zero), m_clock_timer(nullptr), m_periodic_timer(nullptr),
m_clock_timer(nullptr), m_update_timer(nullptr), m_periodic_timer(nullptr),
m_write_irq(*this),
m_write_sqw(*this),
m_century_index(-1),
@ -46,7 +62,8 @@ mc146818_device::mc146818_device(const machine_config &mconfig, device_type type
m_binary(false),
m_hour(false),
m_binyear(false),
m_sqw_state(false)
m_sqw_state(false),
m_tuc(0)
{
}
@ -57,8 +74,8 @@ mc146818_device::mc146818_device(const machine_config &mconfig, device_type type
void mc146818_device::device_start()
{
m_data = make_unique_clear<uint8_t[]>(data_size());
m_last_refresh = machine().time();
m_clock_timer = timer_alloc(TIMER_CLOCK);
m_update_timer = timer_alloc(TIMER_UPDATE);
m_periodic_timer = timer_alloc(TIMER_PERIODIC);
m_write_irq.resolve_safe();
@ -110,6 +127,15 @@ void mc146818_device::device_timer(emu_timer &timer, device_timer_id id, int par
case TIMER_CLOCK:
if (!(m_data[REG_B] & REG_B_SET))
{
m_data[REG_A] |= REG_A_UIP;
m_update_timer->adjust(attotime::from_usec(244));
}
break;
case TIMER_UPDATE:
if (!param)
{
/// TODO: find out how the real chip deals with updates when binary/bcd values are already outside the normal range
int seconds = get_seconds() + 1;
@ -195,12 +221,19 @@ void mc146818_device::device_timer(emu_timer &timer, device_timer_id id, int par
m_data[REG_C] |= REG_C_AF;
}
// set the update-ended interrupt Flag UF
m_data[REG_C] |= REG_C_UF;
update_irq();
m_last_refresh = machine().time();
// defer the update end sequence if update cycle time is non-zero
if (m_tuc)
{
m_update_timer->adjust(attotime::from_usec(m_tuc), 1);
break;
}
}
// clear update in progress and set update ended
m_data[REG_A] &= ~REG_A_UIP;
m_data[REG_C] |= REG_C_UF;
update_irq();
break;
}
}
@ -627,11 +660,6 @@ uint8_t mc146818_device::internal_read(offs_t offset)
{
case REG_A:
data = m_data[REG_A];
// Update In Progress (UIP) time for 32768 Hz is 244+1984usec
/// TODO: support other dividers
/// TODO: don't set this if update is stopped
if ((machine().time() - m_last_refresh) < attotime::from_usec(244+1984))
data |= REG_A_UIP;
break;
case REG_C:

13
src/devices/machine/mc146818.h
View File

@ -157,12 +157,12 @@ protected:
uint8_t m_index;
std::unique_ptr<uint8_t[]> m_data;
attotime m_last_refresh;
static const device_timer_id TIMER_CLOCK = 0;
static const device_timer_id TIMER_PERIODIC = 1;
static const device_timer_id TIMER_UPDATE = 1;
static const device_timer_id TIMER_PERIODIC = 2;
emu_timer *m_clock_timer;
emu_timer *m_update_timer;
emu_timer *m_periodic_timer;
devcb_write_line m_write_irq;
@ -170,10 +170,17 @@ protected:
int m_century_index, m_epoch;
bool m_use_utc, m_binary, m_hour, m_binyear;
bool m_sqw_state;
unsigned m_tuc; // update cycle time
};
class ds1287_device : public mc146818_device
{
public:
ds1287_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
};
// device type definition
DECLARE_DEVICE_TYPE(MC146818, mc146818_device)
DECLARE_DEVICE_TYPE(DS1287, ds1287_device)
#endif // MAME_MACHINE_MC146818_H