what is/where can i find more info on "HI2COUT"

Question

looking to bit-bang the I2C interface of a MCP23017 with an ATtiny13A, a lot of places mention HI2COUT as a method to send data on the I2C bus but i have no clue if this is part of a language or a Library or even a description of what happens when called. so the questions:

1) where can i get info on HI2COUT?

2) if any one has ever interfaces with an MCP23017 can you post the proper sequence to set 1 (or all) pins as output and set HIGH? (this includes start, write address, write register IOCON, ..., stop, etc...)

3) this may be to "Hardware" like for stackoverflow if anyone knows of a site better suited for this question (or may have the answer) please let me know.

Answer 1

Do you mean you're interested in programming the ATtiny13A (so that it can talk to a target device, which happens to be a MCP23017 but that's not an important detail)?

Just guessing, HI2COUT might be the name of a memory-mapped register to output data to the I²C peripheral of a microprocessor. However, looking at the ATtiny13A data sheet and the MCP23017 data sheet, I can't see such a register named. Perhaps that is the name of a register for an I²C peripheral of a different type of microprocessor?

The MCP23017 has I²C hardware built-in--see section 1.3.2 "I²C Interface" starting on page 5 of the MCP23017 data sheet. It will tell you how to do I²C on that device. But assuming it's the ATtiny13A you want to program, it looks as though it has no I²C hardware, so as you say, bit-banging is needed.

I suggest doing an Internet search for "ATtiny13A i2c" and you should be able to find several examples.