SPI vs TWI current consumption

[All4here]

Hello, i am working on Low current consumption project. i have one question. what will be the good option to use the SPI or TWI ? who have less current consumption ?

i have sensor in both option TWI and SPI.now i need to consider the current consumption from communication protocol.

Thank you

[Stian Røed Hafskjold]

The active base current should be similar for both TWI and SPI. So then it's all about how fast you are able to transmit the bytes. SPI can go as fast as 8Mbps, so therefore the total current will be a lot less than with TWI which has a max speed of 400kbps. I guess it then depends on the max speed on the slave you are using.

Other things you should be aware of is that the active current is also dependent on the pin capacitance, with this formula: I = f * V * C. Where f is frequency, V is voltage, and C is capacitance. So with an 8 MHz SCK signal the capacitive load will have a significant impact on the current. A good PCB design is therefore critical. However, this will most likely not be more current than what you will gain with the faster speed.