What is the serial peripheral interface?

The

serial peripheral interface (SPI) is a cheap, four -wire, fully duplex synchronous data current interface of the serial communication that works in the relationship between the main slave. Data transmission in serial devices occurs at one bit at a time, making SPI low -speed interfaces. It is commonly used as an interconnection between integrated circuits with on -board slow peripheral devices that are accessed occasionally. It competes with a parallel data transfer device, but with increasing SPI efficiency, the advantage of the former is reduced. SPI is sometimes referred to as "microwire", although this is considered a protocol of SPI subset.

data transfers by serial peripheral interface occur through a fully duplexed protocol. The data is transmitted and received in both directions simultaneously. SPI applications gain great efficiency in this mode; One such application is between the encoder decodar (CODEC) and the digital signal processor (DSP). Other applications include temperature and pressure sensors, qualityFlash memory.

Whenever two devices of a serial peripheral interface communicate, one device is referred to as "master", while the other device is "slave". The main device initiates all communication by transferring signals to the Slave device. The serial peripheral interface bus can connect more slave devices to a single master.

Serial devices for peripheral interfaces use three registers - inspection register (SPCR), status register (SPSR) and data register (SPDR) - in sending data along with four different signals. The first signal is called serial clock (SCLK), which generates only the main device. This is followed by Master-Out Slave-in (Mosi), Master-in Slave-Out (Miso) and Slave Select (SSN), where "n" is the number of slave devices to which the main device is connected.

in a typical configuration with one slave, an engineer who wants to use a serial peripheral interface would connect SCLTo the entry of Slave. Mosi then transmits data from the main device to the Slave device, while MISO transmits data from Slave to Master. To determine which device is a master and which is a slave, the former connects the Master SSN with the Slave SSN and generates the second discrete input/output signal in general.

If you want to connect multiple slaves to one master in a serial peripheral interface, separate SSN signals are connected from the main device for separate slaves. For example, the SS1 is connected to the slave 1, the SS2 is connected to the Slave 2, etc. Similar to the configuration with one hole, the SCLK is connected from the main device to multiple slaves. Mosi from master to slaves are connected, as well as miso from slaves to master.