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/Documentation/networking/z8530drv.txt

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  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 11Please note that the information in this document may be hopelessly outdated.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