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// license:BSD-3-Clause
// copyright-holders:Vas Crabb
/*
* nld_schmitt.cpp
*
*/
#include "analog/nlid_twoterm.h"
#include "nl_base.h"
#include "nl_errstr.h"
#include "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:
schmitt_trigger_model_t(param_model_t &model)
: m_VTP(model, "VTP")
, m_VTM(model, "VTM")
, m_VI(model, "VI")
, m_RI(model, "RI")
, m_VOH(model, "VOH")
, m_ROH(model, "ROH")
, m_VOL(model, "VOL")
, m_ROL(model, "ROL")
, m_TPLH(model, "TPLH")
, m_TPHL(model, "TPHL")
{
}
param_model_t::value_t m_VTP;
param_model_t::value_t m_VTM;
param_model_t::value_t m_VI;
param_model_t::value_t m_RI;
param_model_t::value_t m_VOH;
param_model_t::value_t m_ROH;
param_model_t::value_t m_VOL;
param_model_t::value_t m_ROL;
param_model_t::value_t m_TPLH;
param_model_t::value_t m_TPHL;
};
NETLIB_OBJECT(schmitt_trigger)
{
NETLIB_CONSTRUCTOR(schmitt_trigger)
, m_A(*this, "A", NETLIB_DELEGATE(input))
, m_supply(*this)
, m_RVI(*this, "RVI")
, m_RVO(*this, "RVO")
, m_stmodel(*this, "STMODEL", "TTL_7414_GATE")
, m_modacc(m_stmodel)
, m_last_state(*this, "m_last_var", 1)
{
register_subalias("Q", "RVO.1");
connect("A", "RVI.1");
// FIXME: need a symbolic reference from connect as well
connect(m_supply.GND(), m_RVI.N());
connect(m_supply.GND(), m_RVO.N());
}
protected:
NETLIB_RESETI()
{
m_last_state = 1;
m_RVI.reset();
m_RVO.reset();
m_RVI.set_G_V_I(plib::reciprocal(m_modacc.m_RI()), m_modacc.m_VI, nlconst::zero());
m_RVO.set_G_V_I(plib::reciprocal(m_modacc.m_ROL()), m_modacc.m_VOL, nlconst::zero());
}
private:
NETLIB_HANDLERI(input)
{
const auto va(m_A.Q_Analog() - m_supply.GND().Q_Analog());
if (m_last_state)
{
if (va < m_modacc.m_VTM)
{
m_last_state = 0;
m_RVO.change_state([this]()
{
m_RVO.set_G_V_I(plib::reciprocal(m_modacc.m_ROH()), m_modacc.m_VOH, nlconst::zero());
});
}
}
else
{
if (va > m_modacc.m_VTP)
{
m_last_state = 1;
m_RVO.change_state([this]()
{
m_RVO.set_G_V_I(plib::reciprocal(m_modacc.m_ROL()), m_modacc.m_VOL, nlconst::zero());
});
}
}
}
analog_input_t m_A;
NETLIB_NAME(power_pins) m_supply;
analog::NETLIB_SUB(twoterm) m_RVI;
analog::NETLIB_SUB(twoterm) m_RVO;
param_model_t m_stmodel;
schmitt_trigger_model_t m_modacc;
state_var<int> m_last_state;
};
NETLIB_DEVICE_IMPL(schmitt_trigger, "SCHMITT_TRIGGER", "STMODEL")
} // namespace devices
} // namespace netlist
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