Ethernet card for MSX
Together with
Yobi I started the design of an ethernet adapter around 2008. I came across the
W5100 where the TCP/IP protocol is handled all by the device itself. From the
moment that the this batch of proto devices were available, Yobi started
writing software for demonstration and test purposes. The W5100 device is
originally intended for embedded use, to connect a standard microcontroller to
a local network or internet. But why not connecting the good old MSX to a
network?
In the past there
were a number of ethernet cards available for MSX based on a Realtek device
(RTL8139), the disadvantage of this device is that only the lowest level is
handled by the hardware. Ofcourse, at that time there were no devices available
with ‘hardware’ TCP stack. All other layers are done in software by the Z80,
which is not quite good/fast with these things... Konamiman had written
software for the earlier ethernet devices, fortunately he also converted the
BIOS to make this ethernet cartridge compatible with existing software. In the
mean time Leonardo Valencia and Marcel Delorme had spent time writing software
as well. With the effort of software guys this project went very well. My part
was the hardware design and some test tools, but this kind of hardware would be
useless without useful software and integration with the operating system.
The W5100 device
is the main device of the cartridge, the others are address decoders, latches
and a FLASH rom. There is some description about programming the ethernet card here, but for details just refer to the W5100 datasheet.
The first ‘final’
PCB was designed to be small and fit into a well known Konami sized case,
unfortunately the UTP connector was too high and would not fit into the
standard cases. Therefore the final design is a bit larger to fit in an
existing case used by Sunrise for MSX.
This project was also intended as an investigation for the coversity project.
For hardware
testing there is a small diagnose tool, it requires a
standard router (with DHCP server enabled) for some communication testing. The
card must be inserted in slot 2, be aware that executing this test program will
erase the BIOS rom! After this test it must be flashed again with the BIOS
image, downloadable from Konamiman.
The cart is
available at Sunrise for MSX, from
prototype to final version:
