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     rc — RISCom/8 multiport card


     device isa
     device rc


     The RISCom/8 is an eight port ISA RS-232C communications multiplexer with a built in RISC
     processor.  It uses a block of sixteen I/O ports in the range 0x200 to 0x3f0 selectable by
     on-board switches or jumpers.  The block must be aligned on a sixteen port boundary.  The
     jumper-selectable hardware interrupt level may be set to be detected during system
     initialization using settings found in the /boot/device.hints file.

     This driver is mostly based on the Cirrus Logic CL-CD180 driver.


     The rc driver provides support for the SDL Communications RISCom/8 boards.


     The following driver specific error messages may be reported:

     rc%d channel%d: interrupt-level buffer overflow  An internal buffer overflow error has
     occurred on the listed channel.  The rc driver will need to be reloaded to correct this.

     rc%d: Bad char chan %d  The channel has obtained a bad set of characters.

     rc%d: Got extra chars chan %d  The rc driver got more characters than expected on the
     channel shown.

     rc%d: data mismatch chan %d ptr %d (%d != %d)  Data sent from channel %d to the rx buffer
     was different then expected.

     rc%d: channel %d command timeout, rc.c line: %d  A command timeout has occurred on the
     channel, the src/sys/dev/rc/rc.c file can be consulted for more information.


     tty(1), ttyname(3), sio(4), tty(4), device.hints(5), comcontrol(8), getty(8), mutex(9),


     The rc driver first appeared in FreeBSD 2.0.5.  This manual page first appeared in
     FreeBSD 5.3.


     This manual page was written by Tom Rhodes <>.


     The rc driver code still uses the spl(9) functions.  These should be replaced by mutex(9)

     The various ttyld_*() functions should be documented.