I have been reading up on the external data bus on these chips and have figured out how to operate them in several different setups. One way that interested me was Design Note #028 that uses a ripple counter to walk out the address but the random speed would be terrible! But if handling large groups of data with sequential processing it would be great.
I have heard you can attach an LCD to the external bus and drive it similarly but I cannot find any AppNotes or examples to see how it works. I would presume it would only be able to drive an 8bit LCD directly or a 16bit with a latch. You would need to implement the RS, RW, R, W, E (whichever the module has) in code but then why not just use PORTB = LCD_Data instead of *EXT_MEM = LCD_DATA?
Is the external memory interface substantial faster or something? Anyways If anyone had an example of this setup that I could learn from or an explanation that would be great.