SAIF stands for Switching Activity Interchange Format. SAIF file presents system dynamic change rate, and usually used in dynamic power analyze.
SAIF stands for Switching Activity Interchange Format. SAIF file presents system dynamic change rate, and usually used in dynamic power analyze.
Concept used in SAIF:
Switching Activity in SAIF file is based on static probability and toggle rate. Following is the defination of Static Probability and Toggle Rate.
Static Probability
Static probability is the probability that a signal is at a specific logic state; it is expressed as a number between 0 and 1. SP1 is the static probability that a signal is at logic-1. Similarly SP0 is that static probability that the signal is at logic-0.
You can calculate the static probability as a ratio of the time period for which the signal is at a certain logic state relative to the total simulation time. For example, if SP1 = 0.70, the signal is at logic 1 state 70 percent of the time. Synopsys power tools use SP1 when modeling switching activity.
Toggle Rate
The toggle rate is the number of logic-0-to-logic-1 and logic-1-to- logic-0 transitions of a design object, such as a net, pin, or port, per unit of time. The toggle rate is denoted by TR.
SAIF Example:
(SAIFVERSION "2.0")
(DIRECTION "backward")
(DESIGN "test")
(DATE "Mon May 11 18:54:04 2009")
(VENDOR "Synopsys, Inc")
(PROGRAM_NAME "Power Compiler")
(VERSION "3.0")
(DIVIDER / )
(TIMESCALE 1 ps)
(DURATION 1195000.00)
(INSTANCE stimulus
(INSTANCE vendY
(PORT
(clock
(T0 600000) (T1 595000) (TX 0)
(TC 119) (IG 0)
)
(reset
(T0 1145000) (T1 50000) (TX 0)
(TC 1) (IG 0)
)
(dummy
(T0 1085000) (T1 100000) (TX 10000)
(TC 10) (IG 0)
)
)
(VIRTUAL_INSTANCE "sequential" data_reg[1]
(PORT
(Q
(T0 995000) (T1 200000) (TX 0)
(TC 12) (IG 0)
)
)
)
(VIRTUAL_INSTANCE "sequential" data_reg[0]
(PORT
(Q
(T0 1035000) (T1 160000) (TX 0)
(TC 7) (IG 0)
)
)
)
)
)
)
Definitions of Terminologies in the SAIF File：
|
T0 |
Duration of time found in logic 0 state. |
|
T1 |
Duration of time found in logic 1 state. |
|
TX |
Duration of time found in unknown “X” state. |
|
TC |
The sum of the rise (0Æ1) and fall (1Æ0) transitions that are captured during monitoring. |
|
IG |
Number of 0Æ X Æ0 and 1 Æ X Æ1 glitches captured during monitoring. |
|
RISE |
Rise transitions in a given state. |
|
FALL |
Fall transitions in a given state. |