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 interrupts 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 routine. This limits the usable baud rates on many machines.