How does SPI work in STM32?

the STM32 SPI interface provides two main functions, supporting either the SPI protocol or the I2S audio protocol. By default, it is the SPI function that is selected. The interface can be configured as the master and in this case, it provides the communication clock (SCK) to the external slave device.

What is slave in SPI?

SPI is a synchronous, full duplex master-slave-based interface. The data from the master or the slave is synchronized on the rising or falling clock edge. Both master and slave can transmit data at the same time. The SPI interface can be either 3-wire or 4-wire. This article focuses on the popular 4-wire SPI interface.

How do I use SPI with DMA STM32?

STM32 SPI Slave Receiver With DMA Mode – LAB

Step1: Open CubeMX & Create New Project.
Step2: Choose The Target MCU & Double-Click Its Name.
Step3: Go To The RCC Clock Configuration.
Step4: Set The System Clock To Be 70MHz or whatever your uC board supports.

Does SPI support slaves having different addresses?

Not possible. You must know the slave address. Otherwise you can just find the address of the slave by programming master to send a test byte to different addresses from 0x00 to 0x7F.

What is SPI NSS signal?

The active-low slave-select (NSS) signal allows support for multiple slave devices on a single bus. It is also used to detect the start and end of a SPI transfer for CP2400/2, and should be connected to the SPI master instead of connection to a static low level signal, e.g. GND.

How do you make a SPI slave?

The slave component’s SPI mode is set by the user with the cpol and cpha GENERIC parameters in the VHDL entity. Each transaction between this SPI slave component and the SPI master must consist of an 8-bit command, followed by a N-bit data transfer.

What is TI mode in SPI?

Motorola and TI mode refer to different configurations of clock polarity (CPOL) and clock phase (CPHA). The clock polarity dictates whether a high or low signal marks a clock, the phase tells the device when to sample the data line. According to your ARM datasheet, you can set CPOL and CPHA for your SPI controller.

How does SPI DMA work?

About SPI. SPI is a hierarquical synchronous communication protocol amongst electronic devices. By means of four pins – Clock, output, input and chip selector – it manages to transfer data between two or more devices.

How many slaves did SPI master communicate?

Each SPI slave that is connected to a master will need a dedicated SS pin on the master. This means the number of pins required on the master will increase as the number of connected slaves increases. It is typical for a SPI master to control two to three slaves and not more.

Is SPI synchronous or asynchronous?

The SPI (Serial Peripheral Interface) has a 4-wire synchronous serial interface. Data communication is enabled with a Chip Select wire (CS). Data is transmitted with a 3-wire interface consisting of wires for serial data input (MOSI), serial data output (MISO) and Serial ClocK (SCK).

How to use the NSS pin in STM32 microcontroller?

Let’s assume that the slave is an STM32 microcontroller which is in slave mode. The master is an STM32 microcontroller, which is in master mode. Here, no need to use the NSS pin. But, if you want to use that pin, then make it as input in the slave side and output on the master side.

Can SPI have multiple master and slave?

That means, the SPI can have multiple masters. But in standard communication, when the device is in master mode, always keep the NSS pin as an output. When the NSS pin is in output mode, it can drive a slave select signal of the single slave. From Figure 1. Let’s assume that the slave is an STM32 microcontroller which is in slave mode.

Can the STM32 SPI hardware operate in half-duplex mode?

The STM32 SPI Hardware is capable of operating in half-duplex mode in 2 configurations. Check the target MCU’s datasheet for more information about each configuration of them if you’re going to use this Half-Duplex mode.

How to maintain a continuous transmit stream in STM32 SPI hardware?

A continuous transmit stream can be maintained if the next data to be transmitted is put in the Tx buffer once the transmission is started. Note that the TXE flag should be ‘1 before any attempt to write the Tx buffer is made. The STM32 SPI Hardware is capable of operating in half-duplex mode in 2 configurations.