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Bus Connectors

It is possible to specify locations where multiple connections can be made at one point, a ``bus subcircuit connector'' (BSC). These can connect to bus terminals (tbus devices from the device menu), bus wires, and other BSCs. A BSC represents a range of existing cell terminals, which are all virtually connected to through the BSC. The terminals can also be connected in the normal way. See the tutorial in 2.2.7 for a description of how to use bus connectors in a schematic.

Like the terminals, the BSCs are created and modified in the subct command in the side menu. The procedure is to first click on each point in the circuit where an external connection is to be made, to identify the connection points, as in normal terminal assignment.

To place a BSC, click on the desired location while holding down both the Shift and Control keys. A terminal symbol will appear at the location, and the prompt line will solicit input. The requested input is two space-separated integers. The first integer is the starting index for the BSC. This is the normal terminal index number that is the minimum index used in the BSC. The terminal index number is the number shown in the box for normal terminals. The second number is the number of connections of the BSC.

For example, suppose that you have given the subcircuit 10 normal terminals, which will be shown in the display as boxes containing integers 0-9. Now place a BSC, and give ``2 4'' at the prompt. The BSC will provide four connections, corresponding to the terminals with indices 2,3,4,5.

There is no limit on the number of BSCs that can be defined. Like ordinary terminals, BSCs can be moved by holding Shift while clicking, then dragging or clicking a second time on the new location. Holding Shift while clicking twice on a BSC will reprompt for the two integers.

Note that if ordinary terminals are subsequently edited, it may be necessary to redefine the BSC's integer parameters, which are shown next to the BSC. The ``x-y'' label indicates the first and last terminal identification associated with the BSC.

It is not an error if the BSC width exceeds the number of defined normal terminals, the corresponding bus connections will simply be open.


next up previous contents index
Next: The symbl Button: Symbolic Up: The subct Button: Set Previous: Virtual Terminals   Contents   Index
Stephen R. Whiteley 2012-04-01