The PPOLL function conducts a Parallel Poll of the IEEE-488 and the 8-bit status message from the IEEE-488 bus is returned. Each bit corresponds to the status of a device which is configured to respond to a parallel poll. You specify either an interface select code or an I/O Path as the function argument. This statement is only supported by the IEEE-488 interface. For example:
ASSIGN @Gpib to 7
Pstatus = PPOLL(@Gpib)
If an interface select code is specified, the bus action is as follows: ATN and EOI are set for greater than or equal to 25 microsec, one byte of data is read from the bus, EOI is released, and ATN is restored to its previous state. If the computer is not the active controller or a primary device address is specified, an error is generated.
