If the ADC is measuring voltages from 0-3.3V, each step in the output value represents a change of. The range of analog voltages is represented as a 10-bit number on the output. The 10-bit property is the resolution of the ADC, or the precision to which it can measure a voltage. The 8-channel part means that it can accept up to 8 different analog voltages, however it can only convert one voltage at any one time. It is an 8-channel, 10-bit analog to digital converter. The ADC used in this example is the MCP3008.

A high Chip Select line tells the SPI device to ignore all of the commands and traffic on the rest of the bus. However, only the selected device has the Chip Select line set low, while all other devices have their CS lines set high. If there are multiple SPI devices, they can all share the same CLK, MOSI, and MISO. Finally, the Chip Select line chooses which particular SPI device is in use.This means the value must be set before the clock is pulsed. The ADC will take the value of the bus on the rising edge of the clock. The MOSI pin sends data from the Raspberry Pi to the ADC.Data is read from the bus after every clock pulse. The MISO pin is a data pin used for the master (in this case the Raspberry Pi) to receive data from the ADC.For the ADC, clock pulses are sampled on their rising edge, on the transition from low to high. The clock pin sense pulses at a regular frequency, the speed at which the Raspberry Pi and SPI device agree to transfer data to each other.These connections are the serial clock (CLK), Master Input Slave Output (MISO), Master Output Slave Input (MOSI) and Chip Select (CS). SPI uses 4 separate connections to communicate with the target device. An analog to digital sensor takes an analog voltage and converts it into a digital number that can be understood by the Raspberry Pi. In this example, we will be learning to use an Analog to Digital Converter (ADC) sensor. These peripheral devices may be either sensors or actuators. The Serial Peripheral Interface (SPI) is a communication protocol used to transfer data between micro-computers like the Raspberry Pi and peripheral devices. A photoresistor decreases resistance (and the voltage across it) when it is exposed to light. This example will use an analog to digital converter to read the analog voltage across a photoresistor.

Usb 3 transfer rate raspberry pi