Hi,
The Toshiba T1200 has an internal expansion port. The port is an 8-bit ISA bus with some pins omitted - basically, it has fewer IRQ and DMA lines but all the basic functionality is there. For example, XTIDE with an appropriately modified PCB would work as all required signals are present. At home I have a list of available pins, which is also found in the service manual.
So, I would like to build an Ethernet card for it, as the original Toshiba LAN cards are impossible to find nowadays. There are single chip ISA Ethernet solutions still in production. I did look at some options and here are my observations. I have not designed anything like this before, so please correct if I'm wrong in my assumptions.
Cirrus Logic CS8900A
This one can apparently operate only on a 16-bit ISA bus. It has a 8-bit mode but this disables interrupts completely, so the card would have to be used in polling mode, which wouldn't be nice.
Davicom DM9000
If I read the datasheet right, this one can be put in a mode where all data transfers are 8 bits wide. It also claims to be an "ISA to Ethernet MAC Controller", and indeed does have an usable interface. According to the datasheet it could do DMA as well.
Silicon Labs CP2200
This one can only do 8-bit data transfers. Looking at it, interfacing this to ISA wouldn't be that hard. No DMA though, but it has a large internal buffer.
Do you have another chip in mind that would be useful here? Or, even better, has someone already done such a design?
The Toshiba T1200 has an internal expansion port. The port is an 8-bit ISA bus with some pins omitted - basically, it has fewer IRQ and DMA lines but all the basic functionality is there. For example, XTIDE with an appropriately modified PCB would work as all required signals are present. At home I have a list of available pins, which is also found in the service manual.
So, I would like to build an Ethernet card for it, as the original Toshiba LAN cards are impossible to find nowadays. There are single chip ISA Ethernet solutions still in production. I did look at some options and here are my observations. I have not designed anything like this before, so please correct if I'm wrong in my assumptions.
Cirrus Logic CS8900A
This one can apparently operate only on a 16-bit ISA bus. It has a 8-bit mode but this disables interrupts completely, so the card would have to be used in polling mode, which wouldn't be nice.
Davicom DM9000
If I read the datasheet right, this one can be put in a mode where all data transfers are 8 bits wide. It also claims to be an "ISA to Ethernet MAC Controller", and indeed does have an usable interface. According to the datasheet it could do DMA as well.
Silicon Labs CP2200
This one can only do 8-bit data transfers. Looking at it, interfacing this to ISA wouldn't be that hard. No DMA though, but it has a large internal buffer.
Do you have another chip in mind that would be useful here? Or, even better, has someone already done such a design?
