13.21.6.3 Signal Map Definition

The signal map of the bus interface specifies the pins on the instance that correspond to the bus definition signals. The bus definition signals are shown on the left, under the Bus Interface Definition. This information includes the name, direction, width, and required properties of the signal.

The pins for your instance are shown in the columns under the Component Instance. The signal element is a drop-down list of the pins that can be mapped for that definition signal. Only pins that have the same direction and width requirements will be shown.

If the Req field of the signal definition is Yes, you must map it to a pin on your instance for this bus interface to be considered legal. If it is No, you can leave it unmapped.

If the Width field is Any there is no restriction on the width for this definition signal. That means a pin of any width on your instance can be mapped to this signal. During bus interface connection, if the instance pins are of differing widths, the bit connections will start from right to left. For example, if a 16-bit bus is connected to an 8-bit bus, the 8-bit bus will be connected to bits 7 down to 0 of the 16-bit bus. The higher bits will be unmapped and tied off at generation time.