examples/snapshot: start, interrupt and resume simulation

examples/snapshot/adder_mos.cir

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+  Example: snsave
+* load a circuit (including transistor models and .tran command)
+* starts transient simulation until stop point
+* store intermediate data to file
+* begin with editing the file location
+* to be run with 'ngspice adder_mos.cir'
+
+.include adder_mos_circ.cir
+
+.control
+*cd to where all files are located
+cd D:\Spice_general\ngspice\examples\snapshot
+set noaskquit
+unset ngdebug
+set noinit
+save vcc#branch 10
+iplot v(10)
+*interrupt condition for the simulation
+stop when time > 500n
+* simulate
+run
+* store snapshot to file
+snsave adder500.snap
+.endc
+
+.END

examples/snapshot/adder_mos_circ.cir

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+*  ADDER - 4 BIT ALL-NAND-GATE BINARY ADDER
+
+*** SUBCIRCUIT DEFINITIONS
+.SUBCKT NAND in1 in2 out VDD
+*   NODES:  INPUT(2), OUTPUT, VCC
+M1 out in2 Vdd Vdd p1 W=3u L=1u
+M2 net.1 in2 0 0 n1 W=3u L=2u
+M3 out in1 Vdd Vdd p1 W=3u L=1u
+M4 out in1 net.1 0 n1 W=3u L=2u
+.ENDS NAND
+
+.SUBCKT ONEBIT 1 2 3 4 5 6
+*   NODES:  INPUT(2), CARRY-IN, OUTPUT, CARRY-OUT, VCC
+X1   1  2  7  6   NAND
+X2   1  7  8  6   NAND
+X3   2  7  9  6   NAND
+X4   8  9 10  6   NAND
+X5   3 10 11  6   NAND
+X6   3 11 12  6   NAND
+X7  10 11 13  6   NAND
+X8  12 13  4  6   NAND
+X9  11  7  5  6   NAND
+.ENDS ONEBIT
+
+.SUBCKT TWOBIT 1 2 3 4 5 6 7 8 9
+*   NODES:  INPUT - BIT0(2) / BIT1(2), OUTPUT - BIT0 / BIT1,
+*           CARRY-IN, CARRY-OUT, VCC
+X1   1  2  7  5 10  9   ONEBIT
+X2   3  4 10  6  8  9   ONEBIT
+.ENDS TWOBIT
+
+.SUBCKT FOURBIT 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
+*   NODES:  INPUT - BIT0(2) / BIT1(2) / BIT2(2) / BIT3(2),
+*           OUTPUT - BIT0 / BIT1 / BIT2 / BIT3, CARRY-IN, CARRY-OUT, VCC
+X1   1  2  3  4  9 10 13 16 15   TWOBIT
+X2   5  6  7  8 11 12 16 14 15   TWOBIT
+.ENDS FOURBIT
+
+*** DEFINE NOMINAL CIRCUIT
+VCC   99  0   DC 3.3V
+VIN1A  1  0   PULSE(0 3 0 10NS 10NS   10NS   50NS)
+VIN1B  2  0   PULSE(0 3 0 10NS 10NS   20NS  100NS)
+VIN2A  3  0   PULSE(0 3 0 10NS 10NS   40NS  200NS)
+VIN2B  4  0   PULSE(0 3 0 10NS 10NS   80NS  400NS)
+VIN3A  5  0   PULSE(0 3 0 10NS 10NS  160NS  800NS)
+VIN3B  6  0   PULSE(0 3 0 10NS 10NS  320NS 1600NS)
+VIN4A  7  0   PULSE(0 3 0 10NS 10NS  640NS 3200NS)
+VIN4B  8  0   PULSE(0 3 0 10NS 10NS 1280NS 6400NS)
+X1     1  2  3  4  5  6  7  8  9 10 11 12  0 13 99 FOURBIT
+*RBIT0  9  0   100K
+*RBIT1 10  0   100K
+*RBIT2 11  0   100K
+*RBIT3 12  0   100K
+*RCOUT 13  0   100K
+
+.TRAN 1NS 1000NS
+
+.model n1 nmos level=8 version=3.3.0
+.model p1 pmos level=8 version=3.3.0
+
+.END

examples/snapshot/adder_snload.script

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+*  SCRIPT: ADDER - 4 BIT BINARY
+* script to reload circuit and continue the simulation
+* begin with editing the file location
+* to be started with 'ngspice adder_snload.script'
+
+.control
+* cd to where all files are located
+cd D:\Spice_general\ngspice\examples\snapshot
+* load circuit and snpashot file
+snload adder_mos_circ.cir adder500.snap
+* continue simulation
+resume
+* plot some node voltages
+plot v(10) v(11) v(12)
+.endc