User guide

13-28
SDF Backannotation
MODULE sub {
SCALE_TYPE=FROM_MTM;
SCALE_FACTORS=1:2:3;
MTM=MINIMUM;
MAP_INNER = X;
(i1 *> o1) = IGNORE;
(i1 *> o1) = ADD { (ia *> oa); }
(i1 *> o1) = ADD { (ib *> ob); }
if (i2==1) (i2 *> o2) = ADD { (ib *> ob); }
}
Understanding the DEVICE Construct
The DEVICE construct specifies the intrinsic delay of a cell or gate.
When VCS reads a DEVICE construct, it backannotates the pin-to-
pin delay generics throughout the cell. How VCS handles the DEVICE
construct depends on whether or not the construct includes an output
port name.
• If DEVICE includes an output port name (for example, (DEVICE
Out1 (1:2:3)), VCS assigns the timing value only to those pin-to-
pin delay generics in the cell with that output port name as their
destination. For example, during backannotation of the device in
Figure 13-3, if the DEVICE construct is
DEVICE Out1 (1:2:3) (1:2:3)
VCS assigns the timing value only to the following generics:
tpdIn1_Out1_R, tpdIn1_Out1_F, tpdIn2_Out1_R, and
tpdIn2_Out1_F
It ignores the generics such as tpdIn1_Out2_R, tpdIn1_Out2_F,
tpdIn2_Out2_R, and tpdIn2_Out2_F.