I2C Controller Read

Read data from I2C peripheral device or I2C peripheral device register

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Libraries:
STM32 Microcontroller Blockset / STM32F1xx Based Boards
STM32 Microcontroller Blockset / STM32F2xx Based Boards
STM32 Microcontroller Blockset / STM32F3xx Based Boards
STM32 Microcontroller Blockset / STM32F4xx Based Boards
STM32 Microcontroller Blockset / STM32F7xx Based Boards
STM32 Microcontroller Blockset / STM32G0xx Based Boards
STM32 Microcontroller Blockset / STM32G4xx Based Boards
STM32 Microcontroller Blockset / STM32H5xx Based Boards
STM32 Microcontroller Blockset / STM32H7xx Based Boards
STM32 Microcontroller Blockset / STM32L4xx Based Boards
STM32 Microcontroller Blockset / STM32L5xx Based Boards
STM32 Microcontroller Blockset / STM32U5xx Based Boards
STM32 Microcontroller Blockset / STM32WBxx Based Boards

Description

The I2C Controller Read block reads serial data from an I2C peripheral device that is connected to the board. Using this block, you can read data from a specific register on the I2C peripheral device. For more information on I2C communication, see Support I2C Communication.

Note

You can run a Simulink^® model containing I2C Controller Read block in Connected IO mode on STM32 Processor based boards. For more information, see Communicate with Hardware Using Connected IO.

Examples

Get Started with STMicroelectronics STM32 Processor Based Boards

Run a Simulink model on STM32 processor.

• Open Model

Ports

Output

Data — Data from I2C peripheral device

vector

The port reads vector data from an I2C device on the board. The size of the data is the value that you specify in the Data size parameter.

Data Types: int8 | uint8 | int16 | uint16 | int32 | uint32 | single | double

Status — Status of read operation

scalar

The port outputs the status of each read request as mentioned in the following table:

Return status codes

Status	Description
0	SUCCESS
1	BUSY
2	ARBITRATION_LOST
4	NO_ACKNOWLEDGE
8	BUS_ERROR
16	BUS_NOT_IN_USE

Dependencies

To enable this port, select the Output error status parameter.

Data Types: uint8

Parameters

I2C module — I2C module to read data

I2C1 (default) | I2C2 | I23C | ...

Specify the I2C module on the board to read data from the I2C peripheral device.

Programmatic Use

Block Parameter: I2CModule

Peripheral byte order — Byte ordering that your I2C peripheral device supports

BigEndian (default) | LittleEndian

The 2-byte ordering options are:

• BigEndian - The most significant byte is sent first over the I2C bus.

• LittleEndian - The least significant byte is sent first over the I2C bus.

Programmatic Use

Block Parameter: PeripheralByteOrder

Peripheral address via — Peripheral address source of I2C

Dialog (default) | Inport

Select the peripheral address source of I2C controller.

Programmatic Use

Block Parameter: PeripheralAddressVia

Peripheral address — The I2C register peripheral address from which to read data

10 (default) | integer greater than or equal to 0

Specify the I2C peripheral address to read the data. You can specify this address in hexadecimal format hex2dec(), for example, ‘hex2dec(‘20’)’.

Programmatic Use

Block Parameter: PeripheralAddress

Enable register access address mode — Option to read from a specific I2C peripheral register

on (default) | off

When you select this parameter, the block reads data from the I2C peripheral register that you specify in the peripheral register address parameter.

When you clear this parameter, the Send no acknowledgment at the end of the transfer and Remove stop bit at the end of data transfer (Repeated start) parameters are displayed. Using these parameters, you can modify the read operation according to your requirements.

Programmatic Use

Block Parameter: RegisterAddressMode

Register address via — Peripheral register address source of I2C

Dialog (default) | Inport

Select the register address source of I2C controller.

Dependencies

To enable this parameter, select Enable register access address mode parameter.

Programmatic Use

Block Parameter: RegisterAddressVia

Peripheral register address — The I2C peripheral register address to read data

0 (default) | integer between 0 and 255

Specify the I2C register address to read the data.

Specify this address as an integer or in hexadecimal format by using hex2dec(), for example, ‘hex2dec(‘20’)’.

For more information on register read/write, see I2C Register Read/Write.

Dependencies

To enable this parameter, select Enable register access address mode parameter.

Programmatic Use

Block Parameter: RegisterAddress

Data type — Data type of data from the I2C peripheral device

uint8 (default) | int8 | int16 | uint16 | int32 | uint32 | single | double

Select the data type in which you want to read from the I2C peripheral device.

Programmatic Use

Block Parameter: DataType

Data size (N) — Data size to read from the I2C peripheral device

1 (default) | integer greater than or equal to 0

Specify the data size that you want to read from the I2C peripheral device for the selected data type.

Programmatic Use

Block Parameter:DataLength

Remove stop bit at the end of data transfer (Repeated start) — Option to remove STOP bit at the end of data transfer

off (default) | on

When the parameter is not selected, the block sends a STOP condition. This condition indicates that the block has terminated the data transmission and that the I2C bus is free for any other I2C Controller block to initiate the new read/write operation.

When you select this parameter, the block sends another START condition followed by an address and read/write bit. The block sends any number of start conditions recursively. Such a repeated START condition allows write operations to the peripheral devices without releasing the bus. No other Controller block interrupts the operation.

Dependencies

To enable this parameter, deselect the Enable register access address mode parameter.

Programmatic Use

Block Parameter: RepeatedStart

Send no acknowledgment at the end of the transfer — Option to send Not Acknowledge bit at the end of data transfer

off (default) | on

When you select this parameter, the I2C Controller Read block sends a NACK (Not Acknowledge) bit to the peripheral device with the final byte.

When the peripheral device receives the NACK, it waits for a STOP condition from the I2C Controller block. The controller block generates either a STOP condition to abort the transfer or a repeated START condition to start a new transfer.

When you deselect this parameter, the I2C Controller Read block sends an ACK (Acknowledge) bit to the peripheral device at the end of every byte. The ACK indicates that the I2C Controller Read block is ready to read the next byte from the peripheral device.

Dependencies

To enable this parameter, deselect the Enable register access address mode parameter.

Programmatic Use

Block Parameter: NoAck

Output error status — Option to display error status during data transmission

off (default) | on

When you select this parameter, the block configures an output port. The port on the block is labeled as Status, indicating that the block outputs the status of the write operation at the output port.

The block outputs the status as a uint8 value. Each value corresponds to a data transfer status.

Status value	Status description
0	SUCCESS
1	BUSY
2	ARBITRATION_LOST
4	NO_ACKNOWLEDGE
8	I2C_BUS_ERROR

Programmatic Use

Block Parameter: OutputStatus

Sample time — Frequency to read data from the I2C peripheral device

-1 (default)

Specify how often the I2C Controller Read block reads data from the I2C peripheral device. When you specify this parameter as-1, the block inherits its sample time based on the context of the block within the model.

Programmatic Use

Block Parameter: SampleTime

Timeout — Specify waiting time to complete read operation

0.001 (default)

You configure Timeout to be the maximum time (in seconds) to wait to complete a read operation.

Programmatic Use

Block Parameter: Timeout

Extended Capabilities

C/C++ Code Generation
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