Embedded Systems & Firmware
What is a characteristic of SPI communication?
- AIt is asynchronous without a clock, using only two wires
- BIt is synchronous with the master driving the clock, sends and receives simultaneously, and selects devices with chip-select lines
- CIt selects devices by address, so two wires suffice for any number of devices
Show answer and explanation
Answer: B. It is synchronous with the master driving the clock, sends and receives simultaneously, and selects devices with chip-select lines
SPI is synchronous communication in which, on the clock driven by the master, data flows simultaneously on a master-to-slave line and a slave-to-master line. Each device gets its own chip-select (CS) line, and only the device whose CS is pulled low communicates. Its simplicity allows clocks of tens of MHz, so it often connects fast parts such as flash memory, displays and ADCs.
- A. That is closer to a UART.
- B. Correct. It is simple and fast.
- C. That describes I2C.