linux/Documentation/networking/z8530drv.txt
<<
>>
Prefs
   1This is a subset of the documentation. To use this driver you MUST have the
   2full package from:
   3
   4Internet:
   5=========
   6
   71. ftp://ftp.ccac.rwth-aachen.de/pub/jr/z8530drv-utils_3.0-3.tar.gz
   8
   92. ftp://ftp.pspt.fi/pub/ham/linux/ax25/z8530drv-utils_3.0-3.tar.gz
  10
  11Please note that the information in this document may be hopelessly outdated.
  12A new version of the documentation, along with links to other important
  13Linux Kernel AX.25 documentation and programs, is available on
  14http://yaina.de/jreuter
  15
  16-----------------------------------------------------------------------------
  17
  18
  19         SCC.C - Linux driver for Z8530 based HDLC cards for AX.25      
  20
  21   ********************************************************************
  22
  23        (c) 1993,2000 by Joerg Reuter DL1BKE <jreuter@yaina.de>
  24
  25        portions (c) 1993 Guido ten Dolle PE1NNZ
  26
  27        for the complete copyright notice see >> Copying.Z8530DRV <<
  28
  29   ******************************************************************** 
  30
  31
  321. Initialization of the driver
  33===============================
  34
  35To use the driver, 3 steps must be performed:
  36
  37     1. if compiled as module: loading the module
  38     2. Setup of hardware, MODEM and KISS parameters with sccinit
  39     3. Attach each channel to the Linux kernel AX.25 with "ifconfig"
  40
  41Unlike the versions below 2.4 this driver is a real network device
  42driver. If you want to run xNOS instead of our fine kernel AX.25
  43use a 2.x version (available from above sites) or read the
  44AX.25-HOWTO on how to emulate a KISS TNC on network device drivers.
  45
  46
  471.1 Loading the module
  48======================
  49
  50(If you're going to compile the driver as a part of the kernel image,
  51 skip this chapter and continue with 1.2)
  52
  53Before you can use a module, you'll have to load it with
  54
  55        insmod scc.o
  56
  57please read 'man insmod' that comes with module-init-tools.
  58
  59You should include the insmod in one of the /etc/rc.d/rc.* files,
  60and don't forget to insert a call of sccinit after that. It
  61will read your /etc/z8530drv.conf.
  62
  631.2. /etc/z8530drv.conf
  64=======================
  65
  66To setup all parameters you must run /sbin/sccinit from one
  67of your rc.*-files. This has to be done BEFORE you can
  68"ifconfig" an interface. Sccinit reads the file /etc/z8530drv.conf
  69and sets the hardware, MODEM and KISS parameters. A sample file is
  70delivered with this package. Change it to your needs.
  71
  72The file itself consists of two main sections.
  73
  741.2.1 configuration of hardware parameters
  75==========================================
  76
  77The hardware setup section defines the following parameters for each
  78Z8530:
  79
  80chip    1
  81data_a  0x300                   # data port A
  82ctrl_a  0x304                   # control port A
  83data_b  0x301                   # data port B
  84ctrl_b  0x305                   # control port B
  85irq     5                       # IRQ No. 5
  86pclock  4915200                 # clock
  87board   BAYCOM                  # hardware type
  88escc    no                      # enhanced SCC chip? (8580/85180/85280)
  89vector  0                       # latch for interrupt vector
  90special no                      # address of special function register
  91option  0                       # option to set via sfr
  92
  93
  94chip    - this is just a delimiter to make sccinit a bit simpler to
  95          program. A parameter has no effect.
  96
  97data_a  - the address of the data port A of this Z8530 (needed)
  98ctrl_a  - the address of the control port A (needed)
  99data_b  - the address of the data port B (needed)
 100ctrl_b  - the address of the control port B (needed)
 101
 102irq     - the used IRQ for this chip. Different chips can use different
 103          IRQs or the same. If they share an interrupt, it needs to be
 104          specified within one chip-definition only.
 105
 106pclock  - the clock at the PCLK pin of the Z8530 (option, 4915200 is
 107          default), measured in Hertz
 108
 109board   - the "type" of the board:
 110
 111           SCC type                 value
 112           ---------------------------------
 113           PA0HZP SCC card          PA0HZP
 114           EAGLE card               EAGLE
 115           PC100 card               PC100
 116           PRIMUS-PC (DG9BL) card   PRIMUS
 117           BayCom (U)SCC card       BAYCOM
 118
 119escc    - if you want support for ESCC chips (8580, 85180, 85280), set
 120          this to "yes" (option, defaults to "no")
 121
 122vector  - address of the vector latch (aka "intack port") for PA0HZP
 123          cards. There can be only one vector latch for all chips!
 124          (option, defaults to 0)
 125
 126special - address of the special function register on several cards.
 127          (option, defaults to 0)
 128
 129option  - The value you write into that register (option, default is 0)
 130
 131You can specify up to four chips (8 channels). If this is not enough,
 132just change
 133
 134        #define MAXSCC 4
 135
 136to a higher value.
 137
 138Example for the BAYCOM USCC:
 139----------------------------
 140
 141chip    1
 142data_a  0x300                   # data port A
 143ctrl_a  0x304                   # control port A
 144data_b  0x301                   # data port B
 145ctrl_b  0x305                   # control port B
 146irq     5                       # IRQ No. 5 (#)
 147board   BAYCOM                  # hardware type (*)
 148#
 149# SCC chip 2
 150#
 151chip    2
 152data_a  0x302
 153ctrl_a  0x306
 154data_b  0x303
 155ctrl_b  0x307
 156board   BAYCOM
 157
 158An example for a PA0HZP card:
 159-----------------------------
 160
 161chip 1
 162data_a 0x153
 163data_b 0x151
 164ctrl_a 0x152
 165ctrl_b 0x150
 166irq 9
 167pclock 4915200
 168board PA0HZP
 169vector 0x168
 170escc no
 171#
 172#
 173#
 174chip 2
 175data_a 0x157
 176data_b 0x155
 177ctrl_a 0x156
 178ctrl_b 0x154
 179irq 9
 180pclock 4915200
 181board PA0HZP
 182vector 0x168
 183escc no
 184
 185A DRSI would should probably work with this:
 186--------------------------------------------
 187(actually: two DRSI cards...)
 188
 189chip 1
 190data_a 0x303
 191data_b 0x301
 192ctrl_a 0x302
 193ctrl_b 0x300
 194irq 7
 195pclock 4915200
 196board DRSI
 197escc no
 198#
 199#
 200#
 201chip 2
 202data_a 0x313
 203data_b 0x311
 204ctrl_a 0x312
 205ctrl_b 0x310
 206irq 7
 207pclock 4915200
 208board DRSI
 209escc no
 210
 211Note that you cannot use the on-board baudrate generator off DRSI
 212cards. Use "mode dpll" for clock source (see below).
 213
 214This is based on information provided by Mike Bilow (and verified
 215by Paul Helay)
 216
 217The utility "gencfg"
 218--------------------
 219
 220If you only know the parameters for the PE1CHL driver for DOS,
 221run gencfg. It will generate the correct port addresses (I hope).
 222Its parameters are exactly the same as the ones you use with
 223the "attach scc" command in net, except that the string "init" must 
 224not appear. Example:
 225
 226gencfg 2 0x150 4 2 0 1 0x168 9 4915200 
 227
 228will print a skeleton z8530drv.conf for the OptoSCC to stdout.
 229
 230gencfg 2 0x300 2 4 5 -4 0 7 4915200 0x10
 231
 232does the same for the BAYCOM USCC card. In my opinion it is much easier
 233to edit scc_config.h... 
 234
 235
 2361.2.2 channel configuration
 237===========================
 238
 239The channel definition is divided into three sub sections for each
 240channel:
 241
 242An example for scc0:
 243
 244# DEVICE
 245
 246device scc0     # the device for the following params
 247
 248# MODEM / BUFFERS
 249
 250speed 1200              # the default baudrate
 251clock dpll              # clock source: 
 252                        #       dpll     = normal half duplex operation
 253                        #       external = MODEM provides own Rx/Tx clock
 254                        #       divider  = use full duplex divider if
 255                        #                  installed (1)
 256mode nrzi               # HDLC encoding mode
 257                        #       nrzi = 1k2 MODEM, G3RUH 9k6 MODEM
 258                        #       nrz  = DF9IC 9k6 MODEM
 259                        #
 260bufsize 384             # size of buffers. Note that this must include
 261                        # the AX.25 header, not only the data field!
 262                        # (optional, defaults to 384)
 263
 264# KISS (Layer 1)
 265
 266txdelay 36              # (see chapter 1.4)
 267persist 64
 268slot    8
 269tail    8
 270fulldup 0
 271wait    12
 272min     3
 273maxkey  7
 274idle    3
 275maxdef  120
 276group   0
 277txoff   off
 278softdcd on                   
 279slip    off
 280
 281The order WITHIN these sections is unimportant. The order OF these
 282sections IS important. The MODEM parameters are set with the first
 283recognized KISS parameter...
 284
 285Please note that you can initialize the board only once after boot
 286(or insmod). You can change all parameters but "mode" and "clock" 
 287later with the Sccparam program or through KISS. Just to avoid 
 288security holes... 
 289
 290(1) this divider is usually mounted on the SCC-PBC (PA0HZP) or not
 291    present at all (BayCom). It feeds back the output of the DPLL 
 292    (digital pll) as transmit clock. Using this mode without a divider 
 293    installed will normally result in keying the transceiver until 
 294    maxkey expires --- of course without sending anything (useful).
 295
 2962. Attachment of a channel by your AX.25 software
 297=================================================
 298
 2992.1 Kernel AX.25
 300================
 301
 302To set up an AX.25 device you can simply type:
 303
 304        ifconfig scc0 44.128.1.1 hw ax25 dl0tha-7
 305
 306This will create a network interface with the IP number 44.128.20.107 
 307and the callsign "dl0tha". If you do not have any IP number (yet) you 
 308can use any of the 44.128.0.0 network. Note that you do not need 
 309axattach. The purpose of axattach (like slattach) is to create a KISS 
 310network device linked to a TTY. Please read the documentation of the 
 311ax25-utils and the AX.25-HOWTO to learn how to set the parameters of
 312the kernel AX.25.
 313
 3142.2 NOS, NET and TFKISS
 315=======================
 316
 317Since the TTY driver (aka KISS TNC emulation) is gone you need
 318to emulate the old behaviour. The cost of using these programs is
 319that you probably need to compile the kernel AX.25, regardless of whether
 320you actually use it or not. First setup your /etc/ax25/axports,
 321for example:
 322
 323        9k6     dl0tha-9  9600  255 4 9600 baud port (scc3)
 324        axlink  dl0tha-15 38400 255 4 Link to NOS
 325
 326Now "ifconfig" the scc device:
 327
 328        ifconfig scc3 44.128.1.1 hw ax25 dl0tha-9
 329
 330You can now axattach a pseudo-TTY:
 331
 332        axattach /dev/ptys0 axlink
 333
 334and start your NOS and attach /dev/ptys0 there. The problem is that
 335NOS is reachable only via digipeating through the kernel AX.25
 336(disastrous on a DAMA controlled channel). To solve this problem,
 337configure "rxecho" to echo the incoming frames from "9k6" to "axlink"
 338and outgoing frames from "axlink" to "9k6" and start:
 339
 340        rxecho
 341
 342Or simply use "kissbridge" coming with z8530drv-utils:
 343
 344        ifconfig scc3 hw ax25 dl0tha-9
 345        kissbridge scc3 /dev/ptys0
 346
 347
 3483. Adjustment and Display of parameters
 349=======================================
 350
 3513.1 Displaying SCC Parameters:
 352==============================
 353
 354Once a SCC channel has been attached, the parameter settings and 
 355some statistic information can be shown using the param program:
 356
 357dl1bke-u:~$ sccstat scc0
 358
 359Parameters:
 360
 361speed       : 1200 baud
 362txdelay     : 36
 363persist     : 255
 364slottime    : 0
 365txtail      : 8
 366fulldup     : 1
 367waittime    : 12
 368mintime     : 3 sec
 369maxkeyup    : 7 sec
 370idletime    : 3 sec
 371maxdefer    : 120 sec
 372group       : 0x00
 373txoff       : off
 374softdcd     : on
 375SLIP        : off
 376
 377Status:
 378
 379HDLC                  Z8530           Interrupts         Buffers
 380-----------------------------------------------------------------------
 381Sent       :     273  RxOver :     0  RxInts :   125074  Size    :  384
 382Received   :    1095  TxUnder:     0  TxInts :     4684  NoSpace :    0
 383RxErrors   :    1591                  ExInts :    11776
 384TxErrors   :       0                  SpInts :     1503
 385Tx State   :    idle
 386
 387
 388The status info shown is:
 389
 390Sent            - number of frames transmitted
 391Received        - number of frames received
 392RxErrors        - number of receive errors (CRC, ABORT)
 393TxErrors        - number of discarded Tx frames (due to various reasons) 
 394Tx State        - status of the Tx interrupt handler: idle/busy/active/tail (2)
 395RxOver          - number of receiver overruns
 396TxUnder         - number of transmitter underruns
 397RxInts          - number of receiver interrupts
 398TxInts          - number of transmitter interrupts
 399EpInts          - number of receiver special condition interrupts
 400SpInts          - number of external/status interrupts
 401Size            - maximum size of an AX.25 frame (*with* AX.25 headers!)
 402NoSpace         - number of times a buffer could not get allocated
 403
 404An overrun is abnormal. If lots of these occur, the product of
 405baudrate and number of interfaces is too high for the processing
 406power of your computer. NoSpace errors are unlikely to be caused by the
 407driver or the kernel AX.25.
 408
 409
 4103.2 Setting Parameters
 411======================
 412
 413
 414The setting of parameters of the emulated KISS TNC is done in the 
 415same way in the SCC driver. You can change parameters by using
 416the kissparms program from the ax25-utils package or use the program 
 417"sccparam":
 418
 419     sccparam <device> <paramname> <decimal-|hexadecimal value>
 420
 421You can change the following parameters:
 422
 423param       : value
 424------------------------
 425speed       : 1200
 426txdelay     : 36
 427persist     : 255
 428slottime    : 0
 429txtail      : 8
 430fulldup     : 1
 431waittime    : 12
 432mintime     : 3
 433maxkeyup    : 7
 434idletime    : 3
 435maxdefer    : 120
 436group       : 0x00
 437txoff       : off
 438softdcd     : on
 439SLIP        : off
 440
 441
 442The parameters have the following meaning:
 443
 444speed:
 445     The baudrate on this channel in bits/sec
 446
 447     Example: sccparam /dev/scc3 speed 9600
 448
 449txdelay:
 450     The delay (in units of 10 ms) after keying of the 
 451     transmitter, until the first byte is sent. This is usually 
 452     called "TXDELAY" in a TNC.  When 0 is specified, the driver 
 453     will just wait until the CTS signal is asserted. This 
 454     assumes the presence of a timer or other circuitry in the 
 455     MODEM and/or transmitter, that asserts CTS when the 
 456     transmitter is ready for data.
 457     A normal value of this parameter is 30-36.
 458
 459     Example: sccparam /dev/scc0 txd 20
 460
 461persist:
 462     This is the probability that the transmitter will be keyed 
 463     when the channel is found to be free.  It is a value from 0 
 464     to 255, and the probability is (value+1)/256.  The value 
 465     should be somewhere near 50-60, and should be lowered when 
 466     the channel is used more heavily.
 467
 468     Example: sccparam /dev/scc2 persist 20
 469
 470slottime:
 471     This is the time between samples of the channel. It is 
 472     expressed in units of 10 ms.  About 200-300 ms (value 20-30) 
 473     seems to be a good value.
 474
 475     Example: sccparam /dev/scc0 slot 20
 476
 477tail:
 478     The time the transmitter will remain keyed after the last 
 479     byte of a packet has been transferred to the SCC. This is 
 480     necessary because the CRC and a flag still have to leave the 
 481     SCC before the transmitter is keyed down. The value depends 
 482     on the baudrate selected.  A few character times should be 
 483     sufficient, e.g. 40ms at 1200 baud. (value 4)
 484     The value of this parameter is in 10 ms units.
 485
 486     Example: sccparam /dev/scc2 4
 487
 488full:
 489     The full-duplex mode switch. This can be one of the following 
 490     values:
 491
 492     0:   The interface will operate in CSMA mode (the normal 
 493          half-duplex packet radio operation)
 494     1:   Fullduplex mode, i.e. the transmitter will be keyed at 
 495          any time, without checking the received carrier.  It 
 496          will be unkeyed when there are no packets to be sent.
 497     2:   Like 1, but the transmitter will remain keyed, also 
 498          when there are no packets to be sent.  Flags will be 
 499          sent in that case, until a timeout (parameter 10) 
 500          occurs.
 501
 502     Example: sccparam /dev/scc0 fulldup off
 503
 504wait:
 505     The initial waittime before any transmit attempt, after the 
 506     frame has been queue for transmit.  This is the length of 
 507     the first slot in CSMA mode.  In full duplex modes it is
 508     set to 0 for maximum performance.
 509     The value of this parameter is in 10 ms units. 
 510
 511     Example: sccparam /dev/scc1 wait 4
 512
 513maxkey:
 514     The maximal time the transmitter will be keyed to send 
 515     packets, in seconds.  This can be useful on busy CSMA 
 516     channels, to avoid "getting a bad reputation" when you are 
 517     generating a lot of traffic.  After the specified time has 
 518     elapsed, no new frame will be started. Instead, the trans-
 519     mitter will be switched off for a specified time (parameter 
 520     min), and then the selected algorithm for keyup will be 
 521     started again.
 522     The value 0 as well as "off" will disable this feature, 
 523     and allow infinite transmission time. 
 524
 525     Example: sccparam /dev/scc0 maxk 20
 526
 527min:
 528     This is the time the transmitter will be switched off when 
 529     the maximum transmission time is exceeded.
 530
 531     Example: sccparam /dev/scc3 min 10
 532
 533idle
 534     This parameter specifies the maximum idle time in full duplex 
 535     2 mode, in seconds.  When no frames have been sent for this 
 536     time, the transmitter will be keyed down.  A value of 0 is
 537     has same result as the fullduplex mode 1. This parameter
 538     can be disabled.
 539
 540     Example: sccparam /dev/scc2 idle off       # transmit forever
 541
 542maxdefer
 543     This is the maximum time (in seconds) to wait for a free channel
 544     to send. When this timer expires the transmitter will be keyed 
 545     IMMEDIATELY. If you love to get trouble with other users you
 546     should set this to a very low value ;-)
 547
 548     Example: sccparam /dev/scc0 maxdefer 240   # 2 minutes
 549
 550
 551txoff:
 552     When this parameter has the value 0, the transmission of packets
 553     is enable. Otherwise it is disabled.
 554
 555     Example: sccparam /dev/scc2 txoff on
 556
 557group:
 558     It is possible to build special radio equipment to use more than 
 559     one frequency on the same band, e.g. using several receivers and 
 560     only one transmitter that can be switched between frequencies.
 561     Also, you can connect several radios that are active on the same 
 562     band.  In these cases, it is not possible, or not a good idea, to 
 563     transmit on more than one frequency.  The SCC driver provides a 
 564     method to lock transmitters on different interfaces, using the 
 565     "param <interface> group <x>" command.  This will only work when 
 566     you are using CSMA mode (parameter full = 0).
 567     The number <x> must be 0 if you want no group restrictions, and 
 568     can be computed as follows to create restricted groups:
 569     <x> is the sum of some OCTAL numbers:
 570
 571     200  This transmitter will only be keyed when all other 
 572          transmitters in the group are off.
 573     100  This transmitter will only be keyed when the carrier 
 574          detect of all other interfaces in the group is off.
 575     0xx  A byte that can be used to define different groups.  
 576          Interfaces are in the same group, when the logical AND 
 577          between their xx values is nonzero.
 578
 579     Examples:
 580     When 2 interfaces use group 201, their transmitters will never be 
 581     keyed at the same time.
 582     When 2 interfaces use group 101, the transmitters will only key 
 583     when both channels are clear at the same time.  When group 301, 
 584     the transmitters will not be keyed at the same time.
 585
 586     Don't forget to convert the octal numbers into decimal before
 587     you set the parameter.
 588
 589     Example: (to be written)
 590
 591softdcd:
 592     use a software dcd instead of the real one... Useful for a very
 593     slow squelch.
 594
 595     Example: sccparam /dev/scc0 soft on
 596
 597
 5984. Problems 
 599===========
 600
 601If you have tx-problems with your BayCom USCC card please check
 602the manufacturer of the 8530. SGS chips have a slightly
 603different timing. Try Zilog...  A solution is to write to register 8 
 604instead to the data port, but this won't work with the ESCC chips. 
 605*SIGH!*
 606
 607A very common problem is that the PTT locks until the maxkeyup timer
 608expires, although interrupts and clock source are correct. In most
 609cases compiling the driver with CONFIG_SCC_DELAY (set with
 610make config) solves the problems. For more hints read the (pseudo) FAQ 
 611and the documentation coming with z8530drv-utils.
 612
 613I got reports that the driver has problems on some 386-based systems.
 614(i.e. Amstrad) Those systems have a bogus AT bus timing which will
 615lead to delayed answers on interrupts. You can recognize these
 616problems by looking at the output of Sccstat for the suspected
 617port. If it shows under- and overruns you own such a system.
 618
 619Delayed processing of received data: This depends on
 620
 621- the kernel version
 622
 623- kernel profiling compiled or not
 624
 625- a high interrupt load
 626
 627- a high load of the machine --- running X, Xmorph, XV and Povray,
 628  while compiling the kernel... hmm ... even with 32 MB RAM ...  ;-)
 629  Or running a named for the whole .ampr.org domain on an 8 MB
 630  box...
 631
 632- using information from rxecho or kissbridge.
 633
 634Kernel panics: please read /linux/README and find out if it
 635really occurred within the scc driver.
 636
 637If you cannot solve a problem, send me
 638
 639- a description of the problem,
 640- information on your hardware (computer system, scc board, modem)
 641- your kernel version
 642- the output of cat /proc/net/z8530
 643
 6444. Thor RLC100
 645==============
 646
 647Mysteriously this board seems not to work with the driver. Anyone
 648got it up-and-running?
 649
 650
 651Many thanks to Linus Torvalds and Alan Cox for including the driver
 652in the Linux standard distribution and their support.
 653
 654Joerg Reuter    ampr-net: dl1bke@db0pra.ampr.org
 655                AX-25   : DL1BKE @ DB0ABH.#BAY.DEU.EU
 656                Internet: jreuter@yaina.de
 657                WWW     : http://yaina.de/jreuter
 658
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.