The fact that 805x family members don't all time the same is one of several reasons that many people using the old BASIC chips, among others, have opted to use port pins rather than using MMIO. Using the port pins, you use up pins, but you have control over the timing. LCD's have very generous timing, but they're slow, and, for the MMIO approach, 805x's are quite stingy with active nRD and nWR time.

If you take your time, you can easily "talk" to an LCD, but if you're to fast, they won't "hear" you.

Using the port pins, you simply write the RS and R/w signal to one port, data to another, and then raise and lower the E strobe before removing the data from the ports in question.

Likewise, if you want to read, you follow the same procedure, but read the data after raising E and then lower it after you read.

The content and sequence you must provide are amply presented in the many published examples. Just don't forget the initialization timing and sequence.

RE