HTBasic provides five levels of IEEE-488 statements: high level transfer, high level bus control, byte level transfer, low level bus control, and interface interrupt control.
The high level OUTPUT and ENTER statements allow you to easily send and receive data on the bus. All the necessary bus addressing commands are automatically generated.
The high level bus control statements allow you to abort transfers, reset the bus interface, clear specific bus devices, lockout local control of devices, return devices to their local state, pass active control to another, configure the parallel poll response, request service, perform a group execute trigger, and conduct parallel and serial polls.
The byte level SEND statement allows more detailed control over the bus. Because the user must generate all the proper bus addressing commands, use of this statement requires a more detailed knowledge about IEEE-488 bus operations.
The low level bus control statements CONTROL, STATUS, READIO, and WRITEIO allow you to directly access the IEEE-488 driver status and control registers and the controller hardware registers.
The interrupt control statements enable, control, and disable interrupts generated by the IEEE-488 interface hardware.
