BOffYou can use the
BOffprocedure to turn off the power to serial port B and to the internal modem.
BOffprocedure switches off power to the SCC and the -5 volt supply if serial port A is not in use. If the internal modem is installed, connected to port B, and switched on, this procedure switches off power to the modem. Otherwise, the
BOffprocedure switches off power to the serial driver chips, unless they are being used by port A.
ASSEMBLY-LANGUAGE INFORMATIONThe MPW development system provides an assembly-language macro to execute the
BOffroutine. That macro calls the
_SerialPowertrap. To call the
_SerialPowertrap directly, you must first put a longword routine selector in the D0 register. For
BOff, the routine selector is $80.