AtTiny lcd

AFLII

A Faster Lcd I2c Interface

So what is this ?

This is a replacement for the PCF8574 LCD-interface board, which is pin but not API compatible.

It is faster and less cpu consuming for the host because the used AtTiny414 takes care of low-level data handling, besides BUSY-flag is used instead of wait-routines which allows for faster and more easy writing the display.

And why should i use this ?

For me this was a getting-to-know the AtTiny414 project, but it also has some advantages above the PCF8574-solution.

Pro`s:

• faster, steering the LCD module is off-loaded from the host. Benchmarked @>300 lines/second
• more efficient by using BUSY instead of wait
• easy API, in essence just push line number and string over i2c. Uses less memory and cpu on host
• cheaper (at least @Mouser, a AtTiny814 costs around 55 cents, where a PCF8574 does 120 cents)
• Backlight dimming !   
• you could incorporate some custom routines
• pin free for user
• you might learn from this :)

Con`s:

• the rest of the world uses PCF8574
• there`s no ready-build hardware available
• API differs from the PCF solution

Todo:

• The WaitBusy should hold I2C communication by clock stretching. We now still need a delay @host side.
• Better PCB design
• More & clearer examples

Schema: