What is SS in SPI?
Chip select (CS) or slave select (SS) is the name of a control line in the SPI bus used to select one (or a set) of the slave device (commonly called “chips”) out of several slave devices connected to the same master device. Figure 1. Single Master and Single slave devices. From Figure 1.
Is SPI a serial?
SPI (Serial Peripheral Interface) is a serial communication protocol originally developed by Motorola that enables communication between nearly any electronic device that supports clocked serial streams. SPI uses a master-slave method for communication that enables high-speed data streaming.
What are the polarity and clock phases of SPI?
SPI Mode: Polarity and Clock Phase. The SPI interface defines no protocol for data exchange, limiting overhead and allowing for high speed data streaming. Clock polarity (CPOL) and clock phase (CPHA) can be specified as ‘0’ or ‘1’ to form four unique modes to provide flexibility in communication between master and slave as shown in Figure 2.
How does the SPI interface work on a clock?
The SPI interface provides the user with flexibility to select the rising or falling edge of the clock to sample and/or shift the data. Please refer to the device data sheet to determine the number of data bits transmitted using the SPI interface. In SPI, the master can select the clock polarity and clock phase.
Can a SPI interface have more than one slave?
SPI devices support much higher clock frequencies compared to I 2 C interfaces. Users should consult the product data sheet for the clock frequency specification of the SPI interface. SPI interfaces can have only one master and can have one or multiple slaves. Figure 1 shows the SPI connection between the master and the slave.
What do you need to know about SPI bus?
We are going to take a quick look at the two basic parameters you want to carefully adjust when setting up an SPI bus: Clock Polarity (CPOL) and Clock Phase (CPHA). SPI is a synchronous protocol. That means the data lines are sampled (and driven) at certain moments in time – in sync with a given clock line.