Actually i finally found the datasheet to the data pump IC here:
http://www.datasheetarchive.com/dl/Datasheets-8/DSA-153646.pdf
Believe it or not, the datapump actually extends a serial interface via the V.21 interface. So technically, you could use the datapump itself as a serial port. Of course, limited to 14.4 (yuck).
But the datapump does use a 5-bit addressing scheme, and 8 databits plus a chipselect, R/W control lines, and an IRQ signal to the host microprocessor (which is probably the VIA).
This is nice, becuase we could put anything in there, within the means of the 8-bit data bus. So technically they do make and support 8-bit based ethernet controllers, so thats easy. But still need a driver and figure out where the "modem" is mapped in the duo addressing system.
http://www.datasheetarchive.com/dl/Datasheets-8/DSA-153646.pdf
Believe it or not, the datapump actually extends a serial interface via the V.21 interface. So technically, you could use the datapump itself as a serial port. Of course, limited to 14.4 (yuck).
But the datapump does use a 5-bit addressing scheme, and 8 databits plus a chipselect, R/W control lines, and an IRQ signal to the host microprocessor (which is probably the VIA).
This is nice, becuase we could put anything in there, within the means of the 8-bit data bus. So technically they do make and support 8-bit based ethernet controllers, so thats easy. But still need a driver and figure out where the "modem" is mapped in the duo addressing system.