IOtech Digital488OEM - Command Descriptions; Bit Set an; Bit Clear Bn

Command Descriptions 3
Control of the Digital 488 is implemented with 17 bus commands, described here in detail. Examples are
given for many of the commands using a Hewlett-Packard 85 computer in the immediate mode. It is
implied that each command is terminated by the 'END LINE' key on the HP-85 in order to execute the
command. The Digital488 bus address should be set to 18 for all examples.
It is necessary that the EXECUTE command (X) follow all command strings sent to the
Digital488. No commands are executed until an X is received by the Digital488.
Bit Set An
The Bit Set command programs a logic one output to a bit described by the argument 'n'. Setting a bit may
represent either a +5 volt or 0 volt output, depending on whether an Invert command (I16) has been sent.
If data is active high (default condition), then Bit Set outputs +5 volts. If multiple bits are to be set within
the same command string, an Execute command (X) must be included after every Bit Set command.
The bit which is being set must have been configured as an output bit by the Configure command to be
valid. The Strobe output line is not pulsed when the Bit Set command is sent.
An Bit n (1 thru 40) is set to logic one
Example:
CLEAR 718
reset the Digital488
OUTPUT 718;"C5X"
configure all ports as output
OUTPUT 718;"A22X"
set bit 22 to a logic one
OUTPUT 718;"A23XA24X"
set bits 23 and 24 to a logic one
Bit Clear Bn
The Bit Clear command will clear to a logic zero an output bit described by the argument 'n'. Clearing
a bit may represent either a 0 volt or +5 volt output, depending on whether an Invert command (I16) has
been sent. If data is active high (default condition), then Bit Clear outputs 0 volts. When multiple
Bit Clear commands are used in the same command string, an Execute command (X) must follow each
command.
The bit that is being cleared must have been defined as an output by the Configure command in order
to be valid. The Strobe output line is not pulsed when the Bit Clear command is sent.
Bn Bit n (1 thru 40) is cleared to a logic 0
Example:
CLEAR 718
reset the Digital488
OUTPUT 718;"C5X"
configure all ports as output
OUTPUT 718;"A7XA8XA9X"
set bits 7, 8, and 9 to +5 volts
OUTPUT 718;"B7X"
clear bit 7 to zero volts
OUTPUT 718;"B8XB9X"
clear bits 8 and 9 to zero volts
Digital488 User’s Manual 7-17-01 Command Descriptions, 3-1