User`s guide

Functional Behavior 7
-9
IO_LEVEL
is an optional device parameter which selects one of the four
AtoD or DtoA interface subcircuits from the device’s I/O
Model. PSpice A/D calls the selected subcircuit
automatically in the event a node connecting to the primitive
also connects to an analog device. If not specified,
IO_LEVEL defaults to 0. Valid values are:
Following are some simple examples of “U” device
declarations:
U1 NAND(2) $G_DPWR $G_DGND 1 2 10 D0_GATE IO_DFT
U2 JKFF(1) $G_DPWR $G_DGND 3 5 200 3 3 10 2 D_293ASTD
+ IO_STD
U3 INV $G_DPWR $G_DGND IN OUT D_INV IO_INV
MNTYMXDLY=3
+ IO_LEVEL=2
For example, the 74393 part could be defined as a subcircuit
composed of “U” devices as shown below.
.subckt 74393 A CLR QA QB QC QD
+ optional: DPWR=$G_DPWR DGND=$G_DGND
+ params: MNTYMXDLY=0 IO_LEVEL=0
UINV inv DPWR DGND
+ CLR CLRBAR D0_GATE IO_STD
+ IO_LEVEL={IO_LEVEL}
U1 jkff(1) DPWR DGND
+ $D_HI CLRBAR A $D_HI $D_HI
+ QA_BUF $D_NC D_393_1 IO_STD
+ MNTYMXDLY={MNTYMXDLY}
+ IO_LEVEL={IO_LEVEL}
U2 jkff(1) DPWR DGND
+ $D_HI CLRBAR QA_BUF $D_HI $D_HI
+ QB_BUF $D_NC D_393_2 IO_STD
0 = the current value of the circuit-wide
DIGIOLVL option (default=1)
1 = AtoD1/DtoA1
2 = AtoD2/DtoA2
3 = AtoD3/DtoA3
4 = AtoD4/DtoA4
Refer to the “Analo
g
/Di
g
ital
Interfaces” chapter for more
information.