Poor Man's Embedded Webserver
No question, all people at egnite GmbH think, that the Ethernut Starter Kits are a real bargain. Some people, however, complain, that even buying the PCB, Ethernet Controller, Ethernet Transformer und RJ45 connector is many times the price of an ISA Network Card. We have to admit, that this is true.
Jochen Beck contributed all details to build such a real cheap solution.
The ISA card shown is a standart 16-Bit-ISA NIC with a RTL8019AS. Just the bracket was removed. No other mods needed at all.
The board in front is a very simple selfmade ATMega128 evaluation board. It contains the reset controller, a RS232 driver, the crystals, the usual ISP socket and -on the left side- a simple switched power supply for 5V/500mA. The port pins are wired to connectors. The wires around the ATMega are ports forgotten to wire to a connector
The DIL-IC between the ATMega board and the ethernet card is the addressbus latch. The free socket right of the latch is just a mismount..
Shows the SRAM (taken from an old motherboard, as like the ISA connector) on the right side and the HEX-inverter on the left. I used a 74HCT14 instead of a 04, because this one was on stock.
The DIL-IC in the middle is a 3 to 8 addressdecoder 74HCT138 and not at all needed. It was intended to control several 74HCT574 to form a data out from the bus for tests or to control a LCD interface. It has not finished yet.
Just another view. The ribbon cables on the left are application specific. Each one connects a I²C-temperature sensor. The black wires at the rear edge of the ATMega evboard connect a third I2C- temperature sensor, glued onto the switching regulator of the power supply.
Ugly, but some wiring is needed. 90% of the wires are used for the address/data bus. The remainder is GND, +5V, Reset and the application specific I²C bus. This PDF will help to get the job done.
Marek Hummel didn't like that wire crap and made simple PCBs.
Download isanut.zip to correctly program the EEPROM on the ISA card.