描述

I am unable to find what the DSP paths in the timing report are reporting. How can I decipher the delays from my DSP48 delays?

For example, two delays for which I do not know the meaning are Tdspcko_ACOUT_AREG and Tdspdo_ACIN_ACOUT.

解决方案

The base of the name describes the type of delay:

Tdspdck_ = setup
Tdspckd_ = hold
Tdspdo_ = propagation delay from input to output
Tdspcko_ = clock to out delay

The next part of the name references the component input pin name:

Tdspckd_ACIN_
Tdspdck_BIN_
Tdspcko_B_
Tdspdo_A_

Finally, the setup, hold, and clock-to-outs use the reference "REG":

Tdspckd_ACIN_REG
Tdspdck_BIN_REG

If the delay is strictly combinatorial, then you will see the component target/output pin listed:

Tdspdo_ACIN_ACOUT

There are also tags that specify whether the preadder or the multiplier are used. If the multiplier does not use the preadder or multiplier, then you might see the following:

Tdspdo_A_P

While a path that uses the preadder and multiplier is notably larger:

Tdspdo_A_P_PREADD_MULT