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writeRead

Write and read data from SPI device

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Add-On Required: This feature requires the MATLAB Support Package for Arduino Hardware add-on.

Syntax

out = writeRead(dev,dataIn)
out = writeRead(dev,dataIn,precision)

Description

out = writeRead(dev,dataIn) writes the data to the SPI device and returns the data from the SPI device as result of the write operation.

example

out = writeRead(dev,dataIn,precision) also specifies the precision.

example

Examples

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This example uses:

Open Live Script

Create a connection to a SPI device on an Arduino® board.

a = arduino('COM6','Mega2560','Libraries','SPI');
Updating server code on board Mega2560 (COM6). This may take a few minutes.

dev = device(a,'SPIChipSelectPin','D46');
writeEnable = bin2dec('0000 0110');
writeRead(dev,writeEnable);

Write data to the SPI EEPROM.

writeCmd = bin2dec('0000 0010');
address = [255 0];
data = [250 155];
dataIn = [writeCmd address data];
out = writeRead(dev,dataIn)
out = 1×5

     0     0     0     0     0

Read data from the SPI EEPROM

readCmd = bin2dec('0000 0011');
dataIn = [readCmd address zeros(1,2)];
out = writeRead(dev,dataIn)
out = 1×5

     0     0     0   250   155

This example uses:

Open Live Script

Create a connection to a SPI device on an Arduino® board.

a = arduino('COM6','Mega2560','Libraries','SPI');
dev = device(a,'SPIChipSelectPin','D46');

Enable write on EEPROM

writeEnable = 6;
writeRead(dev,writeEnable);

Write data to the SPI EEPROM with the precision of uint16.

writeCmd = 2;
address = [0 0];
data = [51200 51201];
dataIn = [writeCmd address data];
out = writeRead(dev,dataIn,'uint16')
out = 1×5 uint16 row vector

   0   0   0   0   0

Read data from the SPI EEPROM with the precision of uint16.

readCmd = 3
readCmd = 3

dataIn = [readCmd address zeros(1,2)];
out = writeRead(dev,dataIn,'uint16')
out = 1×5 uint16 row vector

       0       0       0   51200   51201

Input Arguments

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SPI device connection, specified as a device object.

Data to write, specified as a scalar, vector, hexadecimal, or binary. The range of the values in the array is based on the precision.

Data precision, specified as one of the following character vectors:

  • 'uint8'

  • 'uint16'

  • 'uint32'

  • 'uint64'

The precision must match the size of the SPI device register.

Data can be also be specified in the following formats:

  • hexadecimal

  • binary

  • char

  • string

Output Arguments

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Data read or returned from the SPI device, returned as a scalar or vector.

More About

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Code Generation Using MATLAB Function Block

  • Use writeRead in a MATLAB® Function block with the Simulink® Support Package for Arduino® Hardware to generate code that can be deployed on Arduino Hardware.

  • Values of dataIn is not validated against the precision. The dataIn values will be saturated when it goes beyond the range of the specified precision.

Version History

Introduced in R2014b

See Also

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