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// license:BSD-3-Clause
// copyright-holders:Vas Crabb
/*
* nld_schmitt.cpp
*
*/
#include "nld_schmitt.h"
#include "netlist/analog/nlid_twoterm.h"
#include "netlist/nl_base.h"
#include "netlist/nl_errstr.h"
#include "netlist/solver/nld_solver.h"
namespace netlist
{
namespace devices
{
/*
* Over-simplified TTL Schmitt trigger model
* It's good enough to work for 74xx/74LSxx if it isn't abused too badly
* It would need major changes to support 4000 or 74HCxx behaviour
* The input is over-simplified - it's actually more like a resistor in series with a diode, and can only source current
* Similarly, high output can only source current and low output can only sink current
* Propagation delays are ignored
*
*/
class schmitt_trigger_model_t : public param_model_t
{
public:
schmitt_trigger_model_t(device_t &device, const pstring &name, const pstring &val)
: param_model_t(device, name, val)
, m_VTP(*this, "VTP")
, m_VTM(*this, "VTM")
, m_VI(*this, "VI")
, m_RI(*this, "RI")
, m_VOH(*this, "VOH")
, m_ROH(*this, "ROH")
, m_VOL(*this, "VOL")
, m_ROL(*this, "ROL")
, m_TPLH(*this, "TPLH")
, m_TPHL(*this, "TPHL")
{
}
value_t m_VTP;
value_t m_VTM;
value_t m_VI;
value_t m_RI;
value_t m_VOH;
value_t m_ROH;
value_t m_VOL;
value_t m_ROL;
value_t m_TPLH;
value_t m_TPHL;
};
NETLIB_OBJECT(schmitt_trigger)
{
NETLIB_CONSTRUCTOR(schmitt_trigger)
, m_A(*this, "A")
, m_GND(*this, "GND")
, m_RVI(*this, "RVI")
, m_RVO(*this, "RVO")
, m_model(*this, "MODEL", "TTL_7414_GATE")
, m_last_state(*this, "m_last_var", 1)
, m_is_timestep(false)
{
register_subalias("Q", m_RVO.m_P);
connect(m_A, m_RVI.m_P);
connect(m_GND, m_RVI.m_N);
connect(m_GND, m_RVO.m_N);
}
protected:
NETLIB_RESETI()
{
m_last_state = 1;
m_RVI.reset();
m_RVO.reset();
m_is_timestep = m_RVO.m_P.net().solver()->has_timestep_devices();
m_RVI.set_G_V_I(nlconst::one() / m_model.m_RI, m_model.m_VI, nlconst::zero());
m_RVO.set_G_V_I(nlconst::one() / m_model.m_ROL, m_model.m_VOL, nlconst::zero());
}
NETLIB_UPDATEI()
{
if (m_last_state)
{
if (m_A.Q_Analog() < m_model.m_VTM)
{
m_last_state = 0;
if (m_is_timestep)
m_RVO.update();
m_RVO.set_G_V_I(nlconst::one() / m_model.m_ROH, m_model.m_VOH, nlconst::zero());
m_RVO.solve_later();
}
}
else
{
if (m_A.Q_Analog() > m_model.m_VTP)
{
m_last_state = 1;
if (m_is_timestep)
m_RVO.update();
m_RVO.set_G_V_I(nlconst::one() / m_model.m_ROL, m_model.m_VOL, nlconst::zero());
m_RVO.solve_later();
}
}
}
private:
analog_input_t m_A;
analog_input_t m_GND;
analog::NETLIB_SUB(twoterm) m_RVI;
analog::NETLIB_SUB(twoterm) m_RVO;
schmitt_trigger_model_t m_model;
state_var<int> m_last_state;
bool m_is_timestep;
};
NETLIB_DEVICE_IMPL(schmitt_trigger, "SCHMITT_TRIGGER", "MODEL")
} // namespace devices
} // namespace netlist
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