So, I am trying to control an LCD display with a port expander such as the MCP230008 which is slave to an ATtiny85 (via an I2C bus). The ATtiny85 will be programmed using an Arduino, and for I2C compatibility, I will be using the TinyWire library. Howevever I am not sure how this setup can then be implemented to drive an LCD display, and what libraries I may need.
After some searching, I found libraries designed to drive LCDs using the I2C interface itself, however, here, the LCD does not support I2C but instead is driven by the MCP which uses I2C.
All in all, not sure if this setup is fully feasible... Help is much appreciated.
PS - There are perhaps hassle free ways of achieving the same result as I am trying, but certain design constraints prevent me from using an MCU with more than 8 pins, or an LCD unit with native I2C support, or even using the ATtiny itself to power the LCD. Perhaps SPI is an alternative to I2C here(?), but I don't know much about it.