TCL example scripts

In this post, I will upload sample scripts to refer : (Under cons)

EXAMPLE : 1

For the engineers who are familiar with static timing analysis, as a programmer I want to calculate arrival time, required time, slack at each node using the given circuit. The example script will be able to demonstrate some of the tcl functions. The following circuit 10 nodes excluding (Out node), delay of each node is represented in the brackets. The objective of this program is to write a TCL script to analyse the slack at each and every node using graph based slack analysis.

Brief introduction about the graph based STA :

We need to break the entire program into three sections :

1. Arrival time calculation (AT)

2. Required time calculation (RT)

3. Slack calculation. 

First we need to calculate AT at each node, Let's do hand calculation of arrival time at few nodes. Arrival time at node 'A' is 10 as delay of node  'A' is 10 and then it passes through node 'D' whose delay is '8',  so the arrival time at node 'D' is 18 adding the delay of traversed path. But we can reach D by traversing IN->B->D accounting the delay of 13 (5+8), so we need to choose bigger one of the two arrival times (18,13) and assign that  arrival time to node 'D' in this case it is '18'. We need to repeat the same for all the nodes.

In the second section we need to calculate the required time starting from out node 'O'. In general we might be given required time by the clock specification. But in this case we take RT as the max of all the arrival times.

The above circuit can be represented using the adjacency matrix. Please refer to following link to know more about adjacency matrix. https://en.wikipedia.org/wiki/Adjacency_matrix