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What is the I2C speed of the ATmega328P?
The I2C clock was probed at the ATMEGA328P pin (although I probed it on the MCP4725 side and got the same #’s) I2C Clock… 1.9Khz….
Can you run Twi at a slow speed?
You can run TWI at a slow speed if you want. I2C spec has no maximum time requirements. As a general rule, you run at a high or moderate speed when awake. And sleep as much as possible. This will give good performance and low average current. An idle I2C bus takes no current. An active I2C bus sinks current through its pullups.
Can a slower I2C draw more power than a faster one?
Although you have stated your looking to lower the power requirements, so a slower I2C may draw more power across the pull ups at a slower speed, may have to test that theory to be sure. (Possum Lodge oath) Quando omni flunkus, moritati.
When to check for the ACK in ATmega328P?
Without this line, your code is checking for the ACK at the start of transmit, not when it has completed. In general, whenever you do anything that changes the state of the i2c bus (sending a start bit, sending an address, sending/receiving data), you should wait until the i2c hardware signals it has processed that change and is ready to continue.
What should voltage regulator be for Arduino mega328p?
Change the Arduino AMS1117 voltage regulator to +3.3V. These ICs in Arduino-compatable packages sell for 5 cents each on eBay when buying a strip of 100 or so. Run the Arduino with +5 — +12 through the V-raw pin. I do this with all my Arduino Nanos and have never had a problem running the Mega328p at 16 MHz/+3.3V.
When to change the state of the I2C bus?
In general, whenever you do anything that changes the state of the i2c bus (sending a start bit, sending an address, sending/receiving data), you should wait until the i2c hardware signals it has processed that change and is ready to continue. Thanks for contributing an answer to Electrical Engineering Stack Exchange!