In

Description: Read I/O Byte. This function returns the byte read from an I/O port.

Returns: Byte

Usage: Script or Steady State

Format: In(Port)

Parameters: Port { numeric } { required } { no default }

Any numeric expression, which specifies which I/O port to read. Port must be in the range 0 to 65535

Comments: This function requires that the VTSIO driver be installed. Please refer to the topic, Communicating Directly With Hardware for more details.

If In is used in a statement or an action trigger, it will be evaluated at a very fast rate. In is a high priority function, and should be used sparingly to avoid reducing overall system performance.

Example:

reg = In(0x300);

This reads a byte from CPU input port 300 hex. If this statement appears in a script the read takes place when the script is executed. If this statement appears in steady state, it is updated very rapidly as a high-priority function.