One serious issue with 805x attachment to old and therefore slow, peripherals is that its bus cycle is not extensible, in most cases. Therefore, you have to resolve the issue of read and write cycle length, based on the length of the nRD and nWR strobes from your 805x operating at whatever frequency. That's why I mentioned that you might not be willing to slow down the clock enough to make this feasible.

If the I2C is available and adequate for you, it's WAY easier to use than those old parts from JameCo.

RE