C28x SPI Transmit

Transmit data through Serial Peripheral Interface (SPI) on target

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Libraries:
C2000 Microcontroller Blockset / C2802x
C2000 Microcontroller Blockset / C2803x
C2000 Microcontroller Blockset / C2805x
C2000 Microcontroller Blockset / C2806x
C2000 Microcontroller Blockset / C280x
C2000 Microcontroller Blockset / C281x
C2000 Microcontroller Blockset / C2833x
C2000 Microcontroller Blockset / C2834x
C2000 Microcontroller Blockset / F280013x
C2000 Microcontroller Blockset / F280015x
C2000 Microcontroller Blockset / F28002x
C2000 Microcontroller Blockset / F28003x
C2000 Microcontroller Blockset / F28004x
C2000 Microcontroller Blockset / F2807x
C2000 Microcontroller Blockset / F2837xD
C2000 Microcontroller Blockset / F2837xS
C2000 Microcontroller Blockset / F2838x / C28x
C2000 Microcontroller Blockset / F28M35x / C28x
C2000 Microcontroller Blockset / F28M36x / C28x
C2000 Microcontroller Blockset / F28p65x

Description

The SPI Transmit block supports synchronous, serial peripheral input/output port communications between the processor and external peripherals or other controllers. The block can run in either peripheral or controller mode. In controller mode, the SPISIMO pin transmits data, and the SPISOMI pin receives the data. When controller mode is selected, the SPI initiates the data transfer by sending a serial clock signal (SPICLK), which is used for the entire serial communications link. Data transfers are synchronized to this SPICLK, which enables both controller and peripheral to send and receive data simultaneously. The maximum frequency for the clock is one quarter of the processor clock frequency.

The SPI Transmit block writes data to the transmit buffer, and the data is transmitted to the SPI device. In controller mode, the SPI Transmit block initiates SPI transmission by writing the data to the SPI transmit buffer. The C28x SPI Receive block must be used along with the SPI Transmit block to read the data received in the receive buffer. In peripheral mode, the SPI Receive block is used to read the data in the receive buffer, which is received from the controller. Then, the data is written into the transmit buffer using the SPI Transmit block. From the transmit buffer, the data is sent to the controller.

The sampling rate is inherited from the input port. The supported data type is uint16.

When the SPI transmit interrupt is configured, the transmit FIFO interrupt flags are cleared in the step function instead of the interrupt service routine. After the data is placed in the transmit buffer, the transmit FIFO interrupt is set and the previous transmit interrupt FIFO flags are cleared. Configure the SPI modules for a specific hardware board by navigating to Hardware Implementation > Target hardware resources. Verify that these settings meet the requirements of your application.

Examples

Using SPI to Read and Write Data to SPI EEPROM

Configure and use SPI blocks to read and write data.

Open Model

Ports

Input

Tx — SPI Transmit data

vector

The data written to the device over the SPI interface.

Data Types: uint16

Output

Status — SPI transmit status

0 | 1 | 2

Status of SPI data transmission. Error status values indicate:

• 0 — No errors.

• 1 — A time-out occurred while the block was transmitting data.

• 2 — The transmitted data contains an error.

Dependencies

This port appears only when Enable blocking mode is not selected.

Data Types: uint16

Parameters

Main

SPI module — SPI module to write data

SPI_A (default) | SPI_B | SPI_C | SPI_D

The SPI module to which the SPI peripheral device is connected. Each processor has a different number of modules.

Clock polarity — SPI clock polarity

Rising_edge (default) | Falling_edge

The clock polarity used for SPI communication mode. This parameter must be the same for both transmit and receive blocks.

Clock phase — SPI clock phase

No_delay (default) | Delay_half_cycle

The clock phase used for SPI communication mode. This parameter must be the same for both transmit and receive blocks.

Enable blocking mode — SPI blocking mode enable

off (default) | on

When this option is selected, the algorithm waits until data is sent before continuing processing.

Advanced

Data bits — Number of bits in SPI transfer

8 (default) | integer in [1 16]

Length in bits of each transmitted or received character. For example, if you select 8, the maximum value that can be transmitted using SPI is 2⁸–1. If you send data greater than this value, the buffer overflows. This parameter must be the same for both transmit and receive blocks.

Chip select calling method — Method to select SPI peripheral device

Provided by the SPI peripheral (default) | Explicit GPIO calls

The SPI controller uses these methods to select SPI peripheral devices:

• Provided by the SPI peripheral — The SPI controller uses the STE pin assignment provided in Hardware Implementation > Target hardware resources > SPI to select the peripheral device. peripheral select and deselect are handled by the SPI peripheral.

• Explicit GPIO calls — The SPI controller uses the general purpose input/output pins instead of the STE pin of the SPI peripheral to select/deselect SPI peripheral devices. The SPI Transmit block selects the peripheral using GPIO pins before transmitting data. To deselect the peripheral, you must use the C28x SPI Receive block along with the SPI Transmit block. Use this option only in controller mode. Select the Enable blocking mode option to ensure that the SPI transmission is complete before the peripheral is deselected.

Chip select pin polarity — SPI chip select pin polarity

Active low (default) | Active high

The logic levels supported by chip select pin to select the SPI peripheral device.

• Active low — The device is enabled on logic low. The SPI peripheral device is enabled when its peripheral select pin is set to low.

• Active high — The device is enabled on logic high. The SPI peripheral device is enabled when its peripheral select pin is set to high.

Dependencies

This option appears only when Chip select calling method is set to Explicit GPIO calls.

Chip select pin — SPI peripheral select pin

0 (default) | positive integer scalar

The general purpose input/output pin that serves as the peripheral select for SPI.

Dependencies

This option appears only when Chip select calling method is set to Explicit GPIO calls.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2017b