ngspice/examples/digital/digital_devices/xspice_c4.cir

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Mixed IO types with conversion of Pspice nand and divider.
* This circuit contains a mixture of IO types, including
* analog, digital, user-defined (real), and 'null'.
*
* The circuit demonstrates the use of the digital and
* user-defined node capability to model system-level designs
* such as sampled-data filters. The simulated circuit
* contains a digital oscillator enabled after 100us. The
* square wave oscillator output is divided by 8 with a
* ripple counter. The result is passed through a digital
* filter to convert it to a sine wave.
*
.tran 1e-5 1e-3
.save all
*
v1 1 0 0.0 pulse(0 1 1e-4 1e-6)
r1 1 0 1k
*
abridge1 [1] [enable] atod
.model atod adc_bridge
*
.SUBCKT NAND2 D0A D0B Q0BAR
+ OPTIONAL: DPWR=$G_DPWR DGND=$D_DGND
+ PARAMS: MNTYMXDLY=0 IO_LEVEL=0
U1 NAND(2) DPWR DGND
+ D0A D0B Q0BAR
+ DLY_XYZ IO_STD MNTYMXDLY={MNTYMXDLY} IO_LEVEL={IO_LEVEL}
.MODEL DLY_XYZ UGATE (TPLHMN=8US TPLHTY=10US TPLHMX=15US
+ TPHLMN=8US TPHLTY=10US TPHLMX=15US)
.ENDS NAND2
*
x2000 enable clk clk nand2
*
*** subckt nand2 replaces these
*** aclk [enable clk] clk nand
*** .model nand d_nand (rise_delay=1e-5 fall_delay=1e-5)
*
.subckt DIVIDER8 clock DIV8_O DIV4_O DIV2_O
+ OPTIONAL: DPWR=$G_DPWR DGND=$G_DGND
+ PARAMS: MNTYMXDLY=0 IO_LEVEL=0
U1 DFF(1) DPWR DGND
+ $D_HI $D_HI clock DIV2_O $D_NC DIV2_O
+ D0_EFF IO_STD IO_LEVEL=0 MNTYMXDLY=2
U2 DFF(1) DPWR DGND
+ $D_HI $D_HI DIV2_O DIV4_O $D_NC DIV4_O
+ D0_EFF IO_STD IO_LEVEL=0 MNTYMXDLY=2
U3 DFF(1) DPWR DGND
+ $D_HI $D_HI DIV4_O DIV8_O $D_NC DIV8_O
+ D0_EFF IO_STD IO_LEVEL=0 MNTYMXDLY=2
.MODEL D0_EFF UEFF ()
.ENDS DIVIDER8
*
x1000 clk div8_out div4_out div2_out divider8
*
*** subckt divider8 replaces these
*** adiv2 div2_out clk NULL NULL NULL div2_out dff
*** adiv4 div4_out div2_out NULL NULL NULL div4_out dff
*** adiv8 div8_out div4_out NULL NULL NULL div8_out dff
*** .model dff d_dff
*
abridge2 div8_out enable filt_in node_bridge2
.model node_bridge2 d_to_real (zero=-1 one=1)
*
xfilter filt_in clk filt_out dig_filter
*
abridge3 filt_out a_out node_bridge3
.model node_bridge3 real_to_v
*
rlpf1 a_out oa_minus 10k
*
xlpf 0 oa_minus lpf_out opamp
*
rlpf2 oa_minus lpf_out 10k
clpf lpf_out oa_minus 0.01uF
*
*
.subckt dig_filter filt_in clk filt_out
*
.model n0 real_gain (gain=1.0)
.model n1 real_gain (gain=2.0)
.model n2 real_gain (gain=1.0)
.model g1 real_gain (gain=0.125)
.model zm1 real_delay
.model d0a real_gain (gain=-0.75)
.model d1a real_gain (gain=0.5625)
.model d0b real_gain (gain=-0.3438)
.model d1b real_gain (gain=1.0)
*
an0a filt_in x0a n0
an1a filt_in x1a n1
an2a filt_in x2a n2
*
az0a x0a clk x1a zm1
az1a x1a clk x2a zm1
*
ad0a x2a x0a d0a
ad1a x2a x1a d1a
*
az2a x2a filt1_out g1
az3a filt1_out clk filt2_in zm1
*
an0b filt2_in x0b n0
an1b filt2_in x1b n1
an2b filt2_in x2b n2
*
az0b x0b clk x1b zm1
az1b x1b clk x2b zm1
*
ad0 x2b x0b d0b
ad1 x2b x1b d1b
*
az2b x2b clk filt_out zm1
*
.ends dig_filter
*
*
.subckt opamp plus minus out
*
r1 plus minus 300k
a1 %vd (plus minus) outint lim
.model lim limit (out_lower_limit = -12 out_upper_limit = 12
+ fraction = true limit_range = 0.2 gain=300e3)
r3 outint out 50.0
r2 out 0 1e12
*
.ends opamp
*
.control
run
plot lpf_out v(a_out)
plot v(xlpf.outint)
*eprint xfilter.x1a
eprint div8_out
.endc
*
.end