[TEG]

Originally Posted by pandy71

Yes but Commodore could "discover" this earlier as they created ALL HW environment by themselves - Amiga was founded around custom chipset idea so it is quite natural choice to reduce pin count in IC's (as pins cost money) or integrate whole, multiple chips design into single chip where interconnects are way cheaper. Zorro III reused same Zorro II lines to keep mechanical compatibility - but using custom silicone similar to LPC design could be introduced earlier - both, for cost reduction and for improved performance.
Going from 3.5MHz to 28MHz perhaps could be impossible but to 14MHz perfectly possible. At the beginning of 90's at least one company offered something similar to what we call today SERDES - Am7968/Am7969.
Paula communication with Agnus (DMAL) is example that Commodore was aware of this possibility - why it was not used more frequently? No clue.

Now I better understand why you have in mind but several points:


- According to the Data Sheet, Am7968/Am7969 is from 1994. Description of the chip:

The Am7968 TAXIchip Transmitter and Am7969 TAXIchip Receiver Chipset is a general-purpose inter- face for very high-speed (4–17.5 Mbyte/s, 40–175 Mbaud serially) point-to-point communications over co- axial or fiber-optic media. The TAXIchip set emulates a pseudo-parallel register. They load data into one side and output it on the other, except in this case, the “other” side is separated by a long serial link.

- I don't understand why Paula DMA make you think of multiplexing
[Edit] I realized you mean using the data lines for different things.

That said, it is true that the technology of multiplexing is know since long...

The history of multiplexing goes back to the 1800s, when Samuel Morse developed his telegraph system which enabled long-distance communications. Later in 1874, Thomas Edison invented diplexing to transmit two individual messages over one line at the same time. Later in 1894 and the 1930s, time-division multiplexing (TDM) and frequency division multiplexing (FDM) came into existence. Source

I think the short answer to your question is the lack of R&D funding. In the same line, I always wondered why, having MOS Technology, they did not used it to make (a lot of) money by producing and selling components wanted by the market. I know they did that a little bit by producing logic gates when there was a shortage but it was under pressure.