How fast (time in ms or us) are SPI transfers made using the standard SPI.transfer function on the Arduino Uno?
epalaima:
How fast (time in ms or us) are SPI transfers made using the standard SPI.transfer function on the Arduino Uno?
That depends on the settings you use. The default setting uses 4 MHz so one byte needs about 2µs. The fastest option you have on the UNO uses a clock frequency of 8MHz and needs 1µs per byte transmitted with SPI.transfer(). Keep in mind, that's for one byte, transferring multiple bytes usually needs some time for the surrounding code and you probably won't reach the maximum transfer rate theoretically possible.