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10 11Please note that the information in this document may be hopelessly outdated. 12A new version of the documentation, along with links to other important 13Linux Kernel AX.25 documentation and programs, is available on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