Nokia Display - I2C port expander

Hello

I would like to control Nokia display through I2C shift register (PCA9556). But I can't figure out how I can send infromation byte through one pin. I know how to open or close the pin. Im try different tutorials but I sitll dont understand how I can do it..

Can you someone give me simple explanation how I can write address for I2C shift register with result to see on the pin for example 8-bit of information like 0x05?

Thank you for any help

PCA9556 is a port expander and not a shift register. Which Nokia display?

The common Nokia displays are SPI. You can bit-bang the SPI via the port expander. But you might just as well write directly to the SPI.

David.

david_prentice:
PCA9556 is a port expander and not a shift register.
Which Nokia display?

The common Nokia displays are SPI. You can bit-bang the SPI via the port expander. But you might just as well write directly to the SPI.

David.

84*48 LCD Display Module White Backlight LCD with PCB for Nokia 5110

Yes but I cant use SPI because I do not have any remain free slots. I need to use I2C comunication to drive Nokia display…

If you already have other SPI devices, you simply add the Nokia to the same SPI bus.

The whole point of a bus is to have multiple devices. Just like you have multiple passengers on a bus.

David.

at the price of chips, get a second nano and you get more pins.

how about SPI drives the data and the port expanded drives the chip select?

and you do know the analog pins are digital first, but can be used as analog, so you can use them.

As a general rule, one MCU with more legs is better than two MCUs with few legs. But on most occasions you can rearrange the pin budget to suit a Uno or Mega2560.

Adding an extra SPI slave to an existing SPI bus involves one extra pin per device. Adding an extra I2C slave to an existing I2C bus involves no extra pins at all.

A separate MCU is appropriate for a parallel display with lots of pins e.g. 8080-16 or 8080-18 data bus. SPI displays are easier with the main MCU. I2C adapter for a 16x2 fits directly on the module. There is not an intelligent MCU. Just a port expander.

David.