Specs

The Ethernet is a simple 10Base-T adapter for the LART. It connects through the Kitchen Sink Board. The core of the board is a Crystal CS8900A Ethernet chip, which is supported by Linux. There's also the provision for a bootrom. As there was some room left on the PCB, I added footprints for some FIFOs and a CPLD, offering an 8-bit parallel output port suitable for, say, digital video I/O.

Schematics

Drivers

Both the Ethernet board and the built-in Ethernet on the rev4 KSB need a modified Linux kernel driver.

Usage

To use the Ethernet interface, you need to get an Ethernet address. An Ethernet address, also known as MAC or hardware address, is a unique 48-bit number that identifies a particular network interface (see here for more info). 48-bit Ethernet addresses are usually written down as six two-digit hexadecimal numbers separated by colons (example: 12:34:56:78:90:AB).
There are two ways to get an Ethernet address for your LART. The safest way is to take an old, unused PC Ethernet card and to copy its Ethernet address. The not-so-safe way is to copy the address from an Ethernet card which is in use on a network that you are absolutely sure the LART will never be connected to.

Apart from the Ethernet address you will need an IP address, a broadcast address and a netmask. See the Linux Networking HOWTO for details. Given these four addresses, you can enable the Ethernet interface with three commands:

Below is a sample of what it looks like. Ignore the "eth1:" messages; the driver is trying to find a second Ethernet interface, loudly complaining about its absence. lart #insmod cs89x0.o Using cs89x0.o eth0: cs8900 rev H found at 0xf6008300 cs89x0: No EEPROM, relying on command line.... cs89x0 media RJ-45,<4>cs89x0: Unable to autoprobe IRQ what the heck, we just use IRQ 0 IRQ 0, programmed I/O, MAC 00:00:00:00:00:00 eth1: incorrect signature 0x1c0 eth1: incorrect signature 0x4848 eth1: incorrect signature 0x4848 cs89x0: probing 0x00008300 eth1: request_region(0xf6008300, 0x10) failed cs89x0: probing 0x0000a300 eth1: incorrect signature 0xffff cs89x0: probing 0x0000c300 eth1: incorrect signature 0x21 cs89x0: probing 0x0000e300 eth1: incorrect signature 0x0 cs89x0: no cs8900 or cs8920 detected. Be sure to disable PnP with SETUP lart #ifconfig eth0 hw ether xx:xx:xx:xx:xx:xx lart #ifconfig eth0 IPADDR broadcast BCAST netmask NETMASK eth0: using half-duplex 10Base-T (RJ-45) lart #', "", ""); erow(); ?>
Note that all you will be able to do at this point is to ping the LART; if you want services like a webserver, you will need to install them.