Measurement Computing Digital488/80A - Manual (Page 54)

B - Bit Clear
SYNTAX Bbit Clear bit to logic 0, where bit = bit value from 1 to 40 .
B? Returns bit of the last bit that was cleared.
DESCRIPTION
The Bit Clear (
B ) command clears to a logic 0 an output bit described by the argument bit . Clearing a bit may
represent either a 0 volt or a +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. If multiple bits are to be cleared within the same
command string, then an Execute (
X ) command must follow every Bit Clear ( B ) command.
To be valid, the bit being cleared must have been configured as an output bit, by the Configuration (
C ) command. The
Data Strobe output line is not pulsed when the Bit Clear ( B ) command is sent.
CAUTION
Because the Configuration (C) command is used, the following programming
example(s) will not work properly if the HVCX1 option is installed with a conflicting
hardware configuration. To be safe, remove the HVCX1 board and replace it with the
jumper board to run the example(s).
EXAMPLE
PRINT#1,"CLEAR08" Line 1: Reset the Digital488/80A.
PRINT#1,"OUTPUT08;C5P0X" Line 2: Configure all 5 ports as output; select all 5 ports.
PRINT#1,"OUTPUT08;A7X A8X A9X" Line 3: Set Bits 7, 8, 9 to a logic 1 (+5 volts).
PRINT#1,"OUTPUT08;B7X" Line 4: Clear Bit 7 to a logic 0 (0 volts).
PRINT#1,"OUTPUT08;B8X B9X" Line 5: Clear Bits 8 and 9 to a logic 0 (0 volts).
48 Digital488/80A Commands 967695 Digital488/80A User's Manual