ZSTTY(4)						   BSD Kernel Interfaces Manual 						  ZSTTY(4)

NAME

     zstty, zsc, zs -- Zilog 8530 Serial Communications Controller (SCC) for RS-232C, RS-422, and RS-423

SYNOPSIS

     options PPS_SYNC
     options PPS_TRAILING_EDGE

   alpha (DEC 3000)
     zsc0 at ioasic? offset 0x100000
     zsc1 at ioasic? offset 0x180000
     zstty0    at zsc0 channel ?   # serial ports on B channels
     zstty2    at zsc1 channel ?   # serial ports on B channels
     lkkbd0    at zsc1 channel ?   # keyboard port on A channels
     vsms0     at zsc0 channel ?   # mouse port on A channels

   cesfic
     zsc* at mainbus0
     zstty*    at zsc? channel ?

   mac68k and macppc
     zsc0 at obio?
     zstty*    at zsc? channel ?
     options ZS_TXDMA

   mipsco
     zsc0 at obio0 addr 0xbb000000
     zstty0    at zsc0 channel 0
     zstty1    at zsc0 channel 1

   mvme68k
     zsc* at pcc? ipl 4
     zsc* at pcctwo? ipl 4
     zstty*    at zsc? channel ?

   news68k
     zsc0 at hb0 addr 0xe0d40000 ipl 5 vect 64 flags 0x0    # news1700
     zsc0 at hb1 addr 0xe1780000 ipl 5 vect 64 flags 0x1    # news1200
     zstty0    at zsc0 channel 0
     zstty1    at zsc0 channel 1

   newsmips
     zsc0 at hb0 addr 0xbfec0000 level 1 flags 0x0     # on-board
     zsc1 at hb0 addr 0xb8c40100 level 1 flags 0x1     # expansion board
     zsc2 at hb0 addr 0xb8c40104 level 1 flags 0x1
     zsc0 at ap?
     zstty0    at zsc0 channel 0
     zstty1    at zsc0 channel 1
     zstty2    at zsc1 channel 0
     zstty3    at zsc1 channel 1
     zstty4    at zsc2 channel 0
     zstty5    at zsc2 channel 1

   next68k
     zsc0 at intio? ipl 5
     #zsc1     at intio? ipl 5
     zstty0    at zsc0 channel 0   # ttya
     zstty1    at zsc0 channel 1   # ttyb

   sgimips
     zsc*      at hpc0 offset ?
     zstty*    at zsc? channel ?

   sparc
     zs0  at mainbus0			# sun4c
     zs0  at obio0		   # sun4m
     zs0  at obio0 addr 0xf1000000 level 12  # sun4/200 and sun4/300
     zs0  at obio0 addr 0x01000000 level 12  # sun4/100
     zstty0    at zs0 channel 0 	     # ttya
     zstty1    at zs0 channel 1 	     # ttyb
     zs1  at mainbus0			# sun4c
     zs1  at obio0		   # sun4m
     zs1  at obio0 addr 0xf0000000 level 12  # sun4/200 and sun4/300
     zs1  at obio0 addr 0x00000000 level 12  # sun4/100
     kbd0 at zs1 channel 0		# keyboard
     ms0  at zs1 channel 1		# mouse
     zs2  at obio0 addr 0xe0000000 level 12  # sun4/300
     zstty2    at zs2 channel 0 	     # ttyc
     zstty3    at zs2 channel 1 	     # ttyd

   sun2
     zs0  at obio0 addr 0x002000   # 2/120, 2/170
     zs1  at obmem0 addr 0x780000  # 2/120, 2/170
     zs0  at obio0 addr 0x7f2000   # 2/50
     zs1  at obio0 addr 0x7f1800   # 2/50
     zs2  at mbmem0 addr 0x080800  # 2/120, 2/170 (first sc SCSI)
     zs3  at mbmem0 addr 0x081000  # 2/120, 2/170 (first sc SCSI)
     zs4  at mbmem0 addr 0x084800  # 2/120, 2/170 (second sc SCSI)
     zs5  at mbmem0 addr 0x085000  # 2/120, 2/170 (second sc SCSI)
     zstty*    at zs? channel ?    # ttya
     kbd0 at zstty?	 # keyboard
     ms0  at zstty?	 # mouse

   sun3
     zstty0    at zsc1 channel 0   # ttya
     zstty1    at zsc1 channel 1   # ttyb
     kbd0 at zsc0 channel 0   # keyboard
     ms0  at zsc0 channel 1   # mouse

   x68k
     zsc0 at intio0 addr 0xe98000 intr 112
     zstty0    at zsc0 channel 0	# built-in RS-232C
     ms0  at zsc0 channel 1	   # standard mouse
     #zsc1     at intio0 addr 0xeafc00 intr 113
     #zstty2   at zsc1 channel 0
     #zstty3   at zsc1 channel 1
     #zsc2     at intio0 addr 0xeafc10 intr 114
     #zstty4   at zsc2 channel 0
     #zstty5   at zsc2 channel 1

DESCRIPTION

     The zstty driver provides TTY support for Zilog 8530 Dual UART chips.

     Input and output for each line may set to any baud rate in the range 50 to 38400 (and higher on some machines).

     The PPS_SYNC option enables code to use the Data Carrier Detect (DCD) signal line for attachment to an external precision clock source (e.g.,
     GPS, CDMA) which generates a Pulse Per Second (PPS) signal.  This is used by ntpd(8) to discipline the system clock, and more accurately
     count/measure time.  See options(4) for more discussion.

FILES

   alpha
     /dev/ttyB0

     /dev/ttyB1

   others
     /dev/ttya

     /dev/ttyb

DIAGNOSTICS

     zs0*: fifo overflow
	     The on-chip ``FIFO'' has overflowed and incoming data has been lost.  This generally means the machine is not responding to inter-
	     rupts from the ZS chip fast enough, which can be remedied only by using a lower baud rate.

     zs0*: ring overflow
	     The software input "ring" has overflowed.	This usually means input flow-control is not configured correctly (i.e. incorrect cable
	     wiring).

SEE ALSO

     kbd(4), ms(4), options(4), scc(4), tty(4), ntpd(8)

HISTORY

     The zstty driver was derived from the sparc zs driver supplied with 4.4BSD UNIX.

CAVEATS

     /dev/ttyB1 on alpha is created by MAKEDEV(8) with minor number 2, so the corresponding device should be zstty2, not zstty1.

BUGS

     The old Zilog 8530 chip has a very small FIFO (3 bytes?) and therefore has very strict latency requirements for the interrupt service rou-
     tine.  This limits the usable baud rates on many machines.

BSD
								   June 7, 2011 							       BSD