SPI ส่งข้อมูลได้รวดเร็วอย่างไร

When I2C is too slow, SPI moves data much faster, perfect for displays and SD cards that push lots of bytes. ⚡

SPI trades simplicity for speed. It uses four lines so data can flow both directions at full pace, with no addresses needed.

MOSI means Master Out, Slave In. It carries data from your Arduino out to the connected device.

MISO means Master In, Slave Out. It carries data from the device back to your Arduino on its own dedicated line.

The SCK clock line is driven by the master and times every bit, just like in I2C but typically much faster.

Instead of addresses, SPI uses a chip-select line per device. Pulling CS low tells exactly one device to listen. 🎯

SPI is full duplex: data goes out on MOSI and comes back on MISO at the same instant, which is why it feels so fast.

The cost of speed is wiring. Each extra device needs its own chip-select pin, so SPI uses more pins than I2C.

Arduino includes an SPI library that handles the timing for you. Include it and the shared lines are managed automatically.

Call SPI.begin() once in setup to configure MOSI, MISO, and SCK. Then you control each device with its chip-select pin.

Pick SPI for high speed with a few devices, and I2C when you want many devices on minimal wiring. Each fits a job.

How does SPI choose which device to talk to?

You learned SPI uses MOSI, MISO, SCK, and chip-select for fast full-duplex data, trading extra pins for high speed. ✅