386 lines
15 KiB
Plaintext
386 lines
15 KiB
Plaintext
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specialix.txt -- specialix IO8+ multiport serial driver readme.
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Copyright (C) 1997 Roger Wolff (R.E.Wolff@BitWizard.nl)
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Specialix pays for the development and support of this driver.
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Please DO contact io8-linux@specialix.co.uk if you require
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support.
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This driver was developed in the BitWizard linux device
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driver service. If you require a linux device driver for your
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product, please contact devices@BitWizard.nl for a quote.
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This code is firmly based on the riscom/8 serial driver,
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written by Dmitry Gorodchanin. The specialix IO8+ card
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programming information was obtained from the CL-CD1865 Data
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Book, and Specialix document number 6200059: IO8+ Hardware
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Functional Specification, augmented by document number 6200088:
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Merak Hardware Functional Specification. (IO8+/PCI is also
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called Merak)
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of
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the License, or (at your option) any later version.
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This program is distributed in the hope that it will be
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useful, but WITHOUT ANY WARRANTY; without even the implied
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warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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PURPOSE. See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public
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License along with this program; if not, write to the Free
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Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139,
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USA.
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Intro
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=====
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This file contains some random information, that I like to have online
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instead of in a manual that can get lost. Ever misplace your Linux
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kernel sources? And the manual of one of the boards in your computer?
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Addresses and interrupts
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========================
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Address dip switch settings:
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The dip switch sets bits 2-9 of the IO address.
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9 8 7 6 5 4 3 2
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+-----------------+
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0 | X X X X X X X |
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| | = IoBase = 0x100
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1 | X |
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+-----------------+ ------ RS232 connectors ---->
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edge connector
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V V V
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Base address 0x100 caused a conflict in one of my computers once. I
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haven't the foggiest why. My Specialix card is now at 0x180. My
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other computer runs just fine with the Specialix card at 0x100....
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The card occupies 4 addresses, but actually only two are really used.
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The PCI version doesn't have any dip switches. The BIOS assigns
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an IO address.
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The driver now still autoprobes at 0x100, 0x180, 0x250 and 0x260. If
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that causes trouble for you, please report that. I'll remove
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autoprobing then.
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The driver will tell the card what IRQ to use, so you don't have to
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change any jumpers to change the IRQ. Just use a command line
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argument (irq=xx) to the insmod program to set the interrupt.
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The BIOS assigns the IRQ on the PCI version. You have no say in what
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IRQ to use in that case.
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If your specialix cards are not at the default locations, you can use
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the kernel command line argument "specialix=io0,irq0,io1,irq1...".
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Here "io0" is the io address for the first card, and "irq0" is the
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irq line that the first card should use. And so on.
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Examples.
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You use the driver as a module and have three cards at 0x100, 0x250
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and 0x180. And some way or another you want them detected in that
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order. Moreover irq 12 is taken (e.g. by your PS/2 mouse).
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insmod specialix.o iobase=0x100,0x250,0x180 irq=9,11,15
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The same three cards, but now in the kernel would require you to
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add
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specialix=0x100,9,0x250,11,0x180,15
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to the command line. This would become
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append="specialix=0x100,9,0x250,11,0x180,15"
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in your /etc/lilo.conf file if you use lilo.
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The Specialix driver is slightly odd: It allows you to have the second
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or third card detected without having a first card. This has
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advantages and disadvantages. A slot that isn't filled by an ISA card,
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might be filled if a PCI card is detected. Thus if you have an ISA
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card at 0x250 and a PCI card, you would get:
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sx0: specialix IO8+ Board at 0x100 not found.
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sx1: specialix IO8+ Board at 0x180 not found.
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sx2: specialix IO8+ board detected at 0x250, IRQ 12, CD1865 Rev. B.
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sx3: specialix IO8+ Board at 0x260 not found.
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sx0: specialix IO8+ board detected at 0xd800, IRQ 9, CD1865 Rev. B.
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This would happen if you don't give any probe hints to the driver.
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If you would specify:
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specialix=0x250,11
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you'd get the following messages:
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sx0: specialix IO8+ board detected at 0x250, IRQ 11, CD1865 Rev. B.
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sx1: specialix IO8+ board detected at 0xd800, IRQ 9, CD1865 Rev. B.
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ISA probing is aborted after the IO address you gave is exhausted, and
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the PCI card is now detected as the second card. The ISA card is now
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also forced to IRQ11....
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Baud rates
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==========
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The rev 1.2 and below boards use a CL-CD1864. These chips can only
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do 64kbit. The rev 1.3 and newer boards use a CL-CD1865. These chips
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are officially capable of 115k2.
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The Specialix card uses a 25MHz crystal (in times two mode, which in
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fact is a divided by two mode). This is not enough to reach the rated
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115k2 on all ports at the same time. With this clock rate you can only
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do 37% of this rate. This means that at 115k2 on all ports you are
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going to lose characters (The chip cannot handle that many incoming
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bits at this clock rate.) (Yes, you read that correctly: there is a
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limit to the number of -=bits=- per second that the chip can handle.)
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If you near the "limit" you will first start to see a graceful
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degradation in that the chip cannot keep the transmitter busy at all
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times. However with a central clock this slow, you can also get it to
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miss incoming characters. The driver will print a warning message when
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you are outside the official specs. The messages usually show up in
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the file /var/log/messages .
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The specialix card cannot reliably do 115k2. If you use it, you have
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to do "extensive testing" (*) to verify if it actually works.
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When "mgetty" communicates with my modem at 115k2 it reports:
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got: +++[0d]ATQ0V1H0[0d][0d][8a]O[cb][0d][8a]
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^^^^ ^^^^ ^^^^
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The three characters that have the "^^^" under them have suffered a
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bit error in the highest bit. In conclusion: I've tested it, and found
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that it simply DOESN'T work for me. I also suspect that this is also
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caused by the baud rate being just a little bit out of tune.
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I upgraded the crystal to 66Mhz on one of my Specialix cards. Works
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great! Contact me for details. (Voids warranty, requires a steady hand
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and more such restrictions....)
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(*) Cirrus logic CD1864 databook, page 40.
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Cables for the Specialix IO8+
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=============================
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The pinout of the connectors on the IO8+ is:
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pin short direction long name
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name
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Pin 1 DCD input Data Carrier Detect
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Pin 2 RXD input Receive
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Pin 3 DTR/RTS output Data Terminal Ready/Ready To Send
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Pin 4 GND - Ground
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Pin 5 TXD output Transmit
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Pin 6 CTS input Clear To Send
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-- 6 5 4 3 2 1 --
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+----- -----+
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|__________|
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clip
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Front view of an RJ12 connector. Cable moves "into" the paper.
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(the plug is ready to plug into your mouth this way...)
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NULL cable. I don't know who is going to use these except for
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testing purposes, but I tested the cards with this cable. (It
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took quite a while to figure out, so I'm not going to delete
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it. So there! :-)
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This end goes This end needs
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straight into the some twists in
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RJ12 plug. the wiring.
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IO8+ RJ12 IO8+ RJ12
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1 DCD white -
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- - 1 DCD
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2 RXD black 5 TXD
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3 DTR/RTS red 6 CTS
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4 GND green 4 GND
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5 TXD yellow 2 RXD
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6 CTS blue 3 DTR/RTS
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Same NULL cable, but now sorted on the second column.
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1 DCD white -
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- - 1 DCD
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5 TXD yellow 2 RXD
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6 CTS blue 3 DTR/RTS
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4 GND green 4 GND
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2 RXD black 5 TXD
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3 DTR/RTS red 6 CTS
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This is a modem cable usable for hardware handshaking:
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RJ12 DB25 DB9
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1 DCD white 8 DCD 1 DCD
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2 RXD black 3 RXD 2 RXD
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3 DTR/RTS red 4 RTS 7 RTS
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4 GND green 7 GND 5 GND
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5 TXD yellow 2 TXD 3 TXD
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6 CTS blue 5 CTS 8 CTS
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+---- 6 DSR 6 DSR
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+---- 20 DTR 4 DTR
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This is a modem cable usable for software handshaking:
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It allows you to reset the modem using the DTR ioctls.
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I (REW) have never tested this, "but xxxxxxxxxxxxx
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says that it works." If you test this, please
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tell me and I'll fill in your name on the xxx's.
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RJ12 DB25 DB9
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1 DCD white 8 DCD 1 DCD
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2 RXD black 3 RXD 2 RXD
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3 DTR/RTS red 20 DTR 4 DTR
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4 GND green 7 GND 5 GND
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5 TXD yellow 2 TXD 3 TXD
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6 CTS blue 5 CTS 8 CTS
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+---- 6 DSR 6 DSR
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+---- 4 RTS 7 RTS
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I bought a 6 wire flat cable. It was colored as indicated.
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Check that yours is the same before you trust me on this.
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Hardware handshaking issues.
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============================
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The driver can be compiled in two different ways. The default
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("Specialix DTR/RTS pin is RTS" is off) the pin behaves as DTR when
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hardware handshaking is off. It behaves as the RTS hardware
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handshaking signal when hardware handshaking is selected.
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When you use this, you have to use the appropriate cable. The
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cable will either be compatible with hardware handshaking or with
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software handshaking. So switching on the fly is not really an
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option.
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I actually prefer to use the "Specialix DTR/RTS pin is RTS" option.
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This makes the DTR/RTS pin always an RTS pin, and ioctls to
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change DTR are always ignored. I have a cable that is configured
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for this.
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Ports and devices
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=================
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Port 0 is the one furthest from the card-edge connector.
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Devices:
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You should make the devices as follows:
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bash
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cd /dev
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for i in 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 \
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16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
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do
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echo -n "$i "
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mknod /dev/ttyW$i c 75 $i
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mknod /dev/cuw$i c 76 $i
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done
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echo ""
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If your system doesn't come with these devices preinstalled, bug your
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linux-vendor about this. They have had ample time to get this
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implemented by now.
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You cannot have more than 4 boards in one computer. The card only
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supports 4 different interrupts. If you really want this, contact me
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about this and I'll give you a few tips (requires soldering iron)....
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If you have enough PCI slots, you can probably use more than 4 PCI
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versions of the card though....
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The PCI version of the card cannot adhere to the mechanical part of
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the PCI spec because the 8 serial connectors are simply too large. If
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it doesn't fit in your computer, bring back the card.
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------------------------------------------------------------------------
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Fixed bugs and restrictions:
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- During initialization, interrupts are blindly turned on.
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Having a shadow variable would cause an extra memory
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access on every IO instruction.
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- The interrupt (on the card) should be disabled when we
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don't allocate the Linux end of the interrupt. This allows
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a different driver/card to use it while all ports are not in
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use..... (a la standard serial port)
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== An extra _off variant of the sx_in and sx_out macros are
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now available. They don't set the interrupt enable bit.
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These are used during initialization. Normal operation uses
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the old variant which enables the interrupt line.
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- RTS/DTR issue needs to be implemented according to
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specialix' spec.
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I kind of like the "determinism" of the current
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implementation. Compile time flag?
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== Ok. Compile time flag! Default is how Specialix likes it.
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== Now a config time flag! Gets saved in your config file. Neat!
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- Can you set the IO address from the lilo command line?
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If you need this, bug me about it, I'll make it.
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== Hah! No bugging needed. Fixed! :-)
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- Cirrus logic hasn't gotten back to me yet why the CD1865 can
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and the CD1864 can't do 115k2. I suspect that this is
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because the CD1864 is not rated for 33MHz operation.
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Therefore the CD1864 versions of the card can't do 115k2 on
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all ports just like the CD1865 versions. The driver does
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not block 115k2 on CD1864 cards.
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== I called the Cirrus Logic representative here in Holland.
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The CD1864 databook is identical to the CD1865 databook,
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except for an extra warning at the end. Similar Bit errors
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have been observed in testing at 115k2 on both an 1865 and
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a 1864 chip. I see no reason why I would prohibit 115k2 on
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1864 chips and not do it on 1865 chips. Actually there is
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reason to prohibit it on BOTH chips. I print a warning.
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If you use 115k2, you're on your own.
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- A spiky CD may send spurious HUPs. Also in CLOCAL???
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-- A fix for this turned out to be counter productive.
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Different fix? Current behaviour is acceptable?
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-- Maybe the current implementation is correct. If anybody
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gets bitten by this, please report, and it will get fixed.
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-- Testing revealed that when in CLOCAL, the problem doesn't
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occur. As warned for in the CD1865 manual, the chip may
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send modem intr's on a spike. We could filter those out,
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but that would be a cludge anyway (You'd still risk getting
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a spurious HUP when two spikes occur.).....
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Bugs & restrictions:
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- This is a difficult card to autoprobe.
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You have to WRITE to the address register to even
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read-probe a CD186x register. Disable autodetection?
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-- Specialix: any suggestions?
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- Arbitrary baud rates are not implemented yet.
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If you need this, bug me about it.
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