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writeAndRead

Write and read binary data from SPI instrument

Syntax

A = writeAndRead(OBJ, dataToWrite)

Description

A = writeAndRead(OBJ, dataToWrite) writes the data, dataToWrite, to the instrument connected to interface object OBJ and reads the data available from the instrument as a result of writing dataToWrite. OBJ must be a 1-by-1 SPI interface object. By default, 'uint8' precision is used.

The interface object must be connected to the device using the connect function before any data can be read from the device, otherwise an error is returned. A connected interface object has a ConnectionStatus property value of connected.

SPI protocol operates in full duplex mode, so input and output data transfers happen simultaneously. For every byte written to the device, a byte is read back from the device.

For more information on using the SPI interface and this function, see Configuring SPI Communication and Transmitting Data Over the SPI Interface.

Examples

This example shows how to create a SPI object s, and read and write data.

Construct a spi object called s using Vendor 'aardvark', with BoardIndex of 0, and Port of 0.

s = spi('aardvark', 0, 0);

Connect to the chip.

connect(s);

Read and write to the chip.

dataToWrite = [2 0 0 255]
data = writeAndRead(s, dataToWrite);

Disconnect the SPI device and clean up by clearing the object.

disconnect(s);
clear('s');
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