Interesting speeds.
I made an i2c backpack for my LCD* this weekend. After some tweaking, and boosting the TWI speed to 300kHz, I can do a single command in 384us.
That translates to 1229 ms for a (80 chars + 80 blanks) * 20 reps.
I could take the TWI speed higher, but then I would have to start adding delays, and separate commands.
Currently, I can send an LCD command with single TWI transmission. Just 3 bytes (excluding address).
- Used a MCP23016 and 8-bit LCD interface. With no RW, although it is connected, not used.