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// license:BSD-3-Clause
// copyright-holders:smf, hap
/*
Generic clock signal device
Set the period either with device_t m_clock, or with set_period if it needs
to be more fine-tuned (m_clock has higher priority).
The duty cycle can be changed with set_duty_cycle (default is 50%), or the
pulse width (active time) can be set directly with set_pulse_width.
Output signal at machine start is right after falling edge.
*/
#include "emu.h"
#include "clock.h"
DEFINE_DEVICE_TYPE(CLOCK, clock_device, "clock", "Clock")
clock_device::clock_device(const machine_config &mconfig, const char *tag, device_t *owner, const XTAL &clock) :
device_t(mconfig, CLOCK, tag, owner, clock),
m_signal(0),
m_output(-1),
m_duty(0.5),
m_period(attotime::never),
m_pw(attotime::never),
m_timer_init(nullptr),
m_timer_tick(nullptr),
m_signal_handler(*this)
{
}
void clock_device::device_start()
{
m_signal_handler.resolve_safe();
save_item(NAME(m_signal));
save_item(NAME(m_output));
save_item(NAME(m_duty));
save_item(NAME(m_period));
save_item(NAME(m_pw));
save_item(NAME(m_thigh));
save_item(NAME(m_tlow));
m_timer_init = timer_alloc(FUNC(clock_device::clock_init), this);
m_timer_tick = timer_alloc(FUNC(clock_device::clock_tick), this);
reinit();
}
void clock_device::reinit()
{
if (!m_timer_init)
return;
// not using synchronize(), that may retrigger more than once
m_timer_init->adjust(attotime::zero);
}
void clock_device::output()
{
if (m_signal != m_output)
{
m_output = m_signal;
m_signal_handler(m_output);
}
}
TIMER_CALLBACK_MEMBER(clock_device::clock_init)
{
attotime period = (m_clock > 0) ? attotime::from_hz(m_clock) : m_period;
assert(!period.is_zero());
if (period.is_never())
{
m_timer_tick->adjust(attotime::never);
return;
}
if (!m_pw.is_never())
{
// set timing via pulse width
attotime pw = m_pw;
if (pw > period)
pw = period;
m_thigh = pw;
m_tlow = period - pw;
}
else
{
// set timing via duty cycle
if (m_duty == 0.5)
{
m_thigh = period / 2;
m_tlow = m_thigh;
}
else if (m_duty == 0.0)
{
m_thigh = attotime::zero;
m_tlow = period;
}
else if (m_duty == 1.0)
{
m_thigh = period;
m_tlow = attotime::zero;
}
else
{
double p = period.as_double();
m_thigh = attotime::from_double(m_duty * p);
m_tlow = attotime::from_double((1.0 - m_duty) * p);
}
}
attotime next = m_signal ? m_thigh : m_tlow;
if (next < m_timer_tick->remaining())
m_timer_tick->adjust(next);
}
TIMER_CALLBACK_MEMBER(clock_device::clock_tick)
{
if (m_thigh.is_zero())
m_signal = 0;
else if (m_tlow.is_zero())
m_signal = 1;
else
m_signal ^= 1;
m_timer_tick->adjust(m_signal ? m_thigh : m_tlow);
output();
}
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