scc(4) [netbsd man page]
SCC(4) BSD Kernel Interfaces Manual SCC(4) NAME
scc -- Zilog 8530 Serial Communications Controller interface SYNOPSIS
scc* at ioasic? offset ? DESCRIPTION
The scc driver provides support for the Zilog 8530 Serial Communications Controller (SCC) via the IOASIC found on DECstation 5000 models in the /100, /20, and /240 series (supported by NetBSD/pmax). Each SCC device has two serial ports. The DECstation 5000 model 20 provides one SCC device. Other models provide two, but one port of each device is dedicated to mouse and keyboard input, respectively. Input and output for each line may set to one of following baud rates: 50, 75, 110, 134.5, 150, 300, 600, 1200, 1800, 2400, 4800, 9600, 19200, 38400, or 57600. Speeds up to 230400 are supported by the chip and the motherboard, but speeds higher than 57600 do not work reliably without an external clock signal. FILES
/dev/ttya /dev/ttyb /dev/ttyc /dev/ttyd The mapping from units to serial-hardware outlets is idiosyncratic. The even ports are wired serial connectors and the odd-numbered ports are reserved for mouse and keyboard. On machines with one port like Personal DECstations, the single device is ttya. On the 5000/1xx and 5000/2xx, the first serial port (default serial console) is ttyc and the second port is ttya. SEE ALSO
intro(4), ioasic(4), ttys(5), MAKEDEV(8) HISTORY
The scc driver first appeared in 4.4BSD. The scc driver was also used for the IOASIC SCC found in DEC Alpha model 3000 TurboCHANNEL based systems; NetBSD/alpha has since been con- verted to use the machine-independent zstty(4). BUGS
The IOASIC provides internal DMA channels that can be programmed to transfer up to 4096 bytes of data into, or out, of an SCC without further software intervention. This feature of the IOASIC is not yet supported. The mapping from device-special files (major and minor number) to chip and port is arguably backwards. ULTRIX tries to hide the hardware mapping, but NetBSD does not. Users wanting to use ULTRIX compatible tty names /dev/tty0 and /dev/tty1 for the scc comm-port lines should make links or device-special files which match their hardware setup. BSD
April 24, 2003 BSD
Check Out this Related Man Page
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