I2C Display Design Question (More I/O expanders?)


I designed a display breakout for some DL1416 display modules I like the look of. I used 1x PFC8574 to control the 7-bit data lines to the display via I2C. I still use 6 pins to control things like CE0/CE1 (which display module I’m talking to), and A0/A1 (which position within the chip I’m writing to), Cursor, and ‘Write Data.’

The question I have is what makes sense? Should I add another PFC8574 IO expander and control these six inputs over i2c as well? I suppose then I could use ATtiny85/45 (8pins) with my displays.

I’ve tried to attach a picture of my display breakout here.

Any ideas?



If it works as is I guess leave it, however as you point out it might be nice to control the entire board with 2 pins so I'd be inclined to go that way. For that matter use a 16-bit IOX (like the MCP23017) and you still only need 1 chip.

I've often thought of using these displays but they are SO expensive I can never justify them. The best price I can find right now if about $16, hav eyou found a cheap AND reliable/continuous source for them?



Thanks for the reply. It works with the single 8574, but I started thinking of reducing the pin use. I hadn't heard of the MCP23017. I'll take a look. I did find a stock of these displays for a pretty good price. I don't know how many are out there.