docs: networking: convert baycom.txt to ReST

- add SPDX header;
- adjust titles and chapters, adding proper markups;
- mark code blocks and literals as such;
- mark tables as such;
- adjust identation, whitespaces and blank lines;
- add to networking/index.rst.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Mauro Carvalho Chehab 2020-04-28 00:01:23 +02:00 committed by David S. Miller
parent 20b943f075
commit b5fcf32d7d
3 changed files with 68 additions and 51 deletions

View File

@ -1,26 +1,31 @@
LINUX DRIVERS FOR BAYCOM MODEMS
.. SPDX-License-Identifier: GPL-2.0
Thomas M. Sailer, HB9JNX/AE4WA, <sailer@ife.ee.ethz.ch>
===============================
Linux Drivers for Baycom Modems
===============================
!!NEW!! (04/98) The drivers for the baycom modems have been split into
Thomas M. Sailer, HB9JNX/AE4WA, <sailer@ife.ee.ethz.ch>
The drivers for the baycom modems have been split into
separate drivers as they did not share any code, and the driver
and device names have changed.
This document describes the Linux Kernel Drivers for simple Baycom style
amateur radio modems.
amateur radio modems.
The following drivers are available:
====================================
baycom_ser_fdx:
This driver supports the SER12 modems either full or half duplex.
Its baud rate may be changed via the `baud' module parameter,
Its baud rate may be changed via the ``baud`` module parameter,
therefore it supports just about every bit bang modem on a
serial port. Its devices are called bcsf0 through bcsf3.
This is the recommended driver for SER12 type modems,
however if you have a broken UART clone that does not have working
delta status bits, you may try baycom_ser_hdx.
delta status bits, you may try baycom_ser_hdx.
baycom_ser_hdx:
baycom_ser_hdx:
This is an alternative driver for SER12 type modems.
It only supports half duplex, and only 1200 baud. Its devices
are called bcsh0 through bcsh3. Use this driver only if baycom_ser_fdx
@ -37,45 +42,48 @@ baycom_epp:
The following modems are supported:
ser12: This is a very simple 1200 baud AFSK modem. The modem consists only
of a modulator/demodulator chip, usually a TI TCM3105. The computer
is responsible for regenerating the receiver bit clock, as well as
for handling the HDLC protocol. The modem connects to a serial port,
hence the name. Since the serial port is not used as an async serial
port, the kernel driver for serial ports cannot be used, and this
driver only supports standard serial hardware (8250, 16450, 16550)
======= ========================================================================
ser12 This is a very simple 1200 baud AFSK modem. The modem consists only
of a modulator/demodulator chip, usually a TI TCM3105. The computer
is responsible for regenerating the receiver bit clock, as well as
for handling the HDLC protocol. The modem connects to a serial port,
hence the name. Since the serial port is not used as an async serial
port, the kernel driver for serial ports cannot be used, and this
driver only supports standard serial hardware (8250, 16450, 16550)
par96: This is a modem for 9600 baud FSK compatible to the G3RUH standard.
The modem does all the filtering and regenerates the receiver clock.
Data is transferred from and to the PC via a shift register.
The shift register is filled with 16 bits and an interrupt is signalled.
The PC then empties the shift register in a burst. This modem connects
to the parallel port, hence the name. The modem leaves the
implementation of the HDLC protocol and the scrambler polynomial to
the PC.
par96 This is a modem for 9600 baud FSK compatible to the G3RUH standard.
The modem does all the filtering and regenerates the receiver clock.
Data is transferred from and to the PC via a shift register.
The shift register is filled with 16 bits and an interrupt is signalled.
The PC then empties the shift register in a burst. This modem connects
to the parallel port, hence the name. The modem leaves the
implementation of the HDLC protocol and the scrambler polynomial to
the PC.
picpar: This is a redesign of the par96 modem by Henning Rech, DF9IC. The modem
is protocol compatible to par96, but uses only three low power ICs
and can therefore be fed from the parallel port and does not require
an additional power supply. Furthermore, it incorporates a carrier
detect circuitry.
picpar This is a redesign of the par96 modem by Henning Rech, DF9IC. The modem
is protocol compatible to par96, but uses only three low power ICs
and can therefore be fed from the parallel port and does not require
an additional power supply. Furthermore, it incorporates a carrier
detect circuitry.
EPP: This is a high-speed modem adaptor that connects to an enhanced parallel port.
Its target audience is users working over a high speed hub (76.8kbit/s).
eppfpga: This is a redesign of the EPP adaptor.
EPP This is a high-speed modem adaptor that connects to an enhanced parallel
port.
Its target audience is users working over a high speed hub (76.8kbit/s).
eppfpga This is a redesign of the EPP adaptor.
======= ========================================================================
All of the above modems only support half duplex communications. However,
the driver supports the KISS (see below) fullduplex command. It then simply
starts to send as soon as there's a packet to transmit and does not care
about DCD, i.e. it starts to send even if there's someone else on the channel.
This command is required by some implementations of the DAMA channel
This command is required by some implementations of the DAMA channel
access protocol.
The Interface of the drivers
============================
Unlike previous drivers, these drivers are no longer character devices,
but they are now true kernel network interfaces. Installation is therefore
@ -88,20 +96,22 @@ me for WAMPES which allows attaching a kernel network interface directly.
Configuring the driver
======================
Every time a driver is inserted into the kernel, it has to know which
modems it should access at which ports. This can be done with the setbaycom
utility. If you are only using one modem, you can also configure the
driver from the insmod command line (or by means of an option line in
/etc/modprobe.d/*.conf).
``/etc/modprobe.d/*.conf``).
Examples::
Examples:
modprobe baycom_ser_fdx mode="ser12*" iobase=0x3f8 irq=4
sethdlc -i bcsf0 -p mode "ser12*" io 0x3f8 irq 4
Both lines configure the first port to drive a ser12 modem at the first
serial port (COM1 under DOS). The * in the mode parameter instructs the driver to use
the software DCD algorithm (see below).
serial port (COM1 under DOS). The * in the mode parameter instructs the driver
to use the software DCD algorithm (see below)::
insmod baycom_par mode="picpar" iobase=0x378
sethdlc -i bcp0 -p mode "picpar" io 0x378
@ -115,29 +125,33 @@ Note that both utilities interpret the values slightly differently.
Hardware DCD versus Software DCD
================================
To avoid collisions on the air, the driver must know when the channel is
busy. This is the task of the DCD circuitry/software. The driver may either
utilise a software DCD algorithm (options=1) or use a DCD signal from
the hardware (options=0).
ser12: if software DCD is utilised, the radio's squelch should always be
open. It is highly recommended to use the software DCD algorithm,
as it is much faster than most hardware squelch circuitry. The
disadvantage is a slightly higher load on the system.
======= =================================================================
ser12 if software DCD is utilised, the radio's squelch should always be
open. It is highly recommended to use the software DCD algorithm,
as it is much faster than most hardware squelch circuitry. The
disadvantage is a slightly higher load on the system.
par96: the software DCD algorithm for this type of modem is rather poor.
The modem simply does not provide enough information to implement
a reasonable DCD algorithm in software. Therefore, if your radio
feeds the DCD input of the PAR96 modem, the use of the hardware
DCD circuitry is recommended.
par96 the software DCD algorithm for this type of modem is rather poor.
The modem simply does not provide enough information to implement
a reasonable DCD algorithm in software. Therefore, if your radio
feeds the DCD input of the PAR96 modem, the use of the hardware
DCD circuitry is recommended.
picpar: the picpar modem features a builtin DCD hardware, which is highly
recommended.
picpar the picpar modem features a builtin DCD hardware, which is highly
recommended.
======= =================================================================
Compatibility with the rest of the Linux kernel
===============================================
The serial driver and the baycom serial drivers compete
for the same hardware resources. Of course only one driver can access a given
@ -154,5 +168,7 @@ The parallel port drivers (baycom_par, baycom_epp) now use the parport subsystem
to arbitrate the ports between different client drivers.
vy 73s de
Tom Sailer, sailer@ife.ee.ethz.ch
hb9jnx @ hb9w.ampr.org

View File

@ -43,6 +43,7 @@ Contents:
arcnet
atm
ax25
baycom
.. only:: subproject and html

View File

@ -127,7 +127,7 @@ config BAYCOM_SER_FDX
your serial interface chip. To configure the driver, use the sethdlc
utility available in the standard ax25 utilities package. For
information on the modems, see <http://www.baycom.de/> and
<file:Documentation/networking/baycom.txt>.
<file:Documentation/networking/baycom.rst>.
To compile this driver as a module, choose M here: the module
will be called baycom_ser_fdx. This is recommended.
@ -145,7 +145,7 @@ config BAYCOM_SER_HDX
the driver, use the sethdlc utility available in the standard ax25
utilities package. For information on the modems, see
<http://www.baycom.de/> and
<file:Documentation/networking/baycom.txt>.
<file:Documentation/networking/baycom.rst>.
To compile this driver as a module, choose M here: the module
will be called baycom_ser_hdx. This is recommended.
@ -160,7 +160,7 @@ config BAYCOM_PAR
par96 designs. To configure the driver, use the sethdlc utility
available in the standard ax25 utilities package. For information on
the modems, see <http://www.baycom.de/> and the file
<file:Documentation/networking/baycom.txt>.
<file:Documentation/networking/baycom.rst>.
To compile this driver as a module, choose M here: the module
will be called baycom_par. This is recommended.
@ -175,7 +175,7 @@ config BAYCOM_EPP
designs. To configure the driver, use the sethdlc utility available
in the standard ax25 utilities package. For information on the
modems, see <http://www.baycom.de/> and the file
<file:Documentation/networking/baycom.txt>.
<file:Documentation/networking/baycom.rst>.
To compile this driver as a module, choose M here: the module
will be called baycom_epp. This is recommended.