Try to give me a CMOS 4000 example. >based on XSPICE parts Does the user need to add a AD bridge? We would better to add the AD bridge in the model, so users just need to take them as a analog part, no bridge need.

* **State Machine/4000 series model** I will try to work out the state table for a 4 bit binary counter like the 74HC193 made using the XSPICE STATE MACHINE. There is a 2 bit example at the end of: <http://ngspice.sourceforge.net/docs/ngspice-manual.pdf#subsection.12.4.18> ~~~~ ----------- begin file ------------- * This is an example state.in file. This file * defines a simple 2-bit counter with one input. The * value of this input determines whether the counter counts * up (in = 1) or down (in = 0). 0 0s 0s 0 -> 3 1 -> 1 1 0s 1z 0 -> 0 1 -> 2 2 1z 0s 0 -> 1 1 -> 3 3 1z 1z 0 -> 2 3 1z 1z 1 -> 0 ------------------ end file --------------- ~~~~ * **AD / DA bridges** Don't worry! The user does not need to add AD or DA bridges. :) Please see: <http://sandbox.easyeda.com/editor#id=BVSCAWigC> * **Please note the errors noted in the schematic: they seem to bugs in the Sandbox version** This example does nothing useful but shows how these devices can be used directly with analogue parts at the input and output. They **do** require a power supply because they behave like real devices: >their input thresholds and output voltages roughly track the supply voltage; >the outputs get more resistive at low supply voltages; >they stop working if the suppliy voltage drops too low; >their outputs drop to zero with zero supply voltage. Pure XSPICE devices do none of these good things. More about the logic devices: This is different from the logic gates in the EasyEDA Libs (which are based on XSPICE) in that it does not need the ADC and DAC Bridges to connect analogue signals, loads and probes into it. It is also different from logic gates in many other simulation tools because it does require a power supply. This is so that if a simulation is run with the supply ramped up from zero - to assist ngspice in finding the right initial conditions for the simulation - or if the sim is run at different supply voltages, then the input threshold levels and the output voltage swing track the supply voltage. Behavioural logic devices in many other simulators do not track the supply voltage and this can cause confusion where logic devices with a wide supply range such as 74C and 4000 series or some of the low voltage CMOS devices are used with variable or poorly regulated supplies. The supply pins for the device are named VDD for the positive and VSS for the negative rails respectively. To reduce the wires needed to be shown in the schematic, the VDD and VSS supply pins for the gate are hidden. To connect to them all that is needed is for a positive rail with a VDD netlabel and a negative rail with a VSS netlabel to exist in the schematic. This technique works even if the rails in the schematic actually have different names, such as RAIL and GND, as in this example. Alternatively, the rails can be wired directly to the device supply pins in the normal way. To do this the device pins must be made visible. Then the supply rail netlabels have no effect on the supply connectivity to the device. Select U1, press the 'I' hotkey and untick 'Hidden Pin' to show the supply pins. Other features of this EasyEDA logic device are that input and output over-rail voltage excursions are clamped to the appropriate rail and so will cause excessive current flow as seen in a real device. A supply voltage above an absolute maximum of approximately 18V or a reverse polarity will also cause excessive current flow. ** Please note: these new devices are NOT the same as the ones I have already put in the library and described in this thread:** <https://easyeda.com/bbs_view_1223.htm> and here: <https://easyeda.com/project_view_An-EasyEDA-logic-family_t3Xf8qI0U.htm> When I have done some more testing, the new logic devices will go into the library and any models already there of the same name (such as INVEE and NAND3EE etc) will be replaced. They will have the same function and behaviour but will then all be using the new models. :)