i have a 16x2 lcd display with HD44780 driver.
ive got it programmed and connected to my arduino, my question is,
can i connect the display up to an attiny84 20pu IC?
theoretically it should work, i can happilly make an AVR shield to program the IC via arduino like the tiny45/85 chips i just want to double check the compatibility between the tiny84 and display before spending almost £6 on a chip that wont be compatible.
No reason why it shouldn't work. And you're getting ripped off for the chip, they should be like $1-2, and the attiny84a is a strictly better part, and cheaper, get that instead.
DrAzzy:
No reason why it shouldn't work. And you're getting ripped off for the chip, they should be like $1-2, and the attiny84a is a strictly better part, and cheaper, get that instead.
brilliant, cheers, £3 each those 84a's
I will also suggest that you use the I2C backpack with that screen (You use up almost all the pins otherwise just on the screen); In that case, you should be sure to use a recent version of ATTinyCore (json board manager url in my sig) - it has a special version of Wire that automagically selects the proper implementation of I2C functionality for your chip, so you can use code you wrote for an atmega on an attiny without modification, even though I2C is provided by a USI instead of a TWI peripheral.
DrAzzy:
I will also suggest that you use the I2C backpack with that screen (You use up almost all the pins otherwise just on the screen); In that case, you should be sure to use a recent version of ATTinyCore (json board manager url in my sig) - it has a special version of Wire that automagically selects the proper implementation of I2C functionality for your chip, so you can use code you wrote for an atmega on an attiny without modification, even though I2C is provided by a USI instead of a TWI peripheral.
whoosh, that went right over my head. ive got the board pack installed already, that bit i understood.
im making my own circuit board to plug the display into if that makes much of a difference, but i2c and so on went over my head.
Those displays are available in two forms, with and without an "I2C Backpack". Without the backpack, you control them with like.... 7 pins, plus however you handle the backlight (IIRC the screens do not have the series resistor), using some variant of the LiquidCrystal library. With the backpack, you control it with 2 pins, SCL and SDA, with some variant of the LiquidCrystal_I2C library. The backpack also has the pot on it to adjust contrast - otherwise you need to supply that as well.