Spi Class Reference

Detailed Description

This file defines the SPI interface for libmraa

    mraa::Spi* spi;

    spi = new mraa::Spi(0);

    uint8_t data[] = {0x00, 100};
    uint8_t rxBuf[2];
    uint8_t *recv;
    while (running == 0) {
        int i;
        for (i = 90; i < 130; i++) {
            data[1] = i;
            recv = spi->write(data, 2);
            printf("Writing -%i",i);
            if (recv) {
                printf("RECIVED-%i-%i\n",recv[0],recv[1]);
                free(recv);
            }
            usleep(100000);
        }
        for (i = 130; i > 90; i--) {
            data[1] = i;
            if (spi->transfer(data, rxBuf, 2) == MRAA_SUCCESS) {
                printf("Writing -%i",i);
                printf("RECIVED-%i-%i\n",rxBuf[0],rxBuf[1]);
            }
            usleep(100000);
        }

    }
    delete spi;

Public Member Functions
	Spi (int bus)
	~Spi ()
mraa_result_t	mode (Spi_Mode mode)
mraa_result_t	frequency (int hz)
uint8_t	writeByte (uint8_t data)
uint8_t *	write (uint8_t *txBuf, int length)
mraa_result_t	transfer (uint8_t *txBuf, uint8_t *rxBuf, int length)
mraa_result_t	lsbmode (bool lsb)
mraa_result_t	bitPerWord (unsigned int bits)

Constructor & Destructor Documentation

Spi ( int  bus )

inline

Initialise SPI object using the board mapping to set muxes

Parameters

bus	to use, as listed in the platform definition, normally 0

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~Spi ( )

inline

Closes spi bus

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Member Function Documentation

mraa_result_t mode ( Spi_Mode  mode )

inline

Set the SPI device mode. see spidev0-3

Parameters

mode	the mode. See Linux spidev doc

Returns

Result of operation

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mraa_result_t frequency ( int  hz )

inline

Set the SPI device operating clock frequency

Parameters

hz	the frequency to set in hz

Returns

Result of operation

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uint8_t writeByte ( uint8_t  data )

inline

Write single byte to the SPI device

Parameters

data	the byte to send

Returns

data received on the miso line

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uint8_t* write ( uint8_t *  txBuf, int  length  )

inline

Write buffer of bytes to SPI device The pointer return has to be free'd by the caller. It will return a NULL pointer in cases of error

@param txBuf buffer to send
@param length size of buffer to send
@return uint8_t* data received on the miso line. Same length as passed in

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mraa_result_t transfer ( uint8_t *  txBuf, uint8_t *  rxBuf, int  length  )

inline

Transfer data to and from SPI device Receive pointer may be null if return data is not needed.

Parameters

data	buffer to send
rxBuf	buffer to optionally receive data from spi device
length	size of buffer to send

Returns

Result of operation

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mraa_result_t lsbmode ( bool  lsb )

inline

Change the SPI lsb mode

Parameters

lsb	Use least significant bit transmission - 0 for msbi

Returns

Result of operation

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mraa_result_t bitPerWord ( unsigned int  bits )

inline

Set bits per mode on transaction, default is 8

Parameters

bits	bits per word

Returns

Result of operation

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The documentation for this class was generated from the following file:

• /var/lib/jenkins/workspace/mraa-doc-stable/api/mraa/spi.hpp