LJ_chSPI_CLOCK_FACTOR
LJ_chSPI_MOSI_PIN_NUM
LJ_chSPI_MISO_PIN_NUM
LJ_chSPI_CLK_PIN_NUM
LJ_chSPI_CS_PIN_NUM
Following is example pseudocode to configure SPI communication:
//First, configure the SPI communication.
//Enable automatic chip-select control.
AddRequest(lngHandle, LJ_ioPUT_CONFIG, LJ_chSPI_AUTO_CS,1,0,0);
//Do not disable automatic digital i/o direction configuration.
AddRequest(lngHandle, LJ_ioPUT_CONFIG, LJ_chSPI_DISABLE_DIR_CONFIG,0,0,0);
//Mode A: CPHA=1, CPOL=1.
AddRequest(lngHandle, LJ_ioPUT_CONFIG, LJ_chSPI_MODE,0,0,0);
//Maximum clock rate (~100kHz).
AddRequest(lngHandle, LJ_ioPUT_CONFIG, LJ_chSPI_CLOCK_FACTOR,0,0,0);
//Set MOSI to FIO2.
AddRequest(lngHandle, LJ_ioPUT_CONFIG, LJ_chSPI_MOSI_PIN_NUM,2,0,0);
//Set MISO to FIO3.
AddRequest(lngHandle, LJ_ioPUT_CONFIG, LJ_chSPI_MISO_PIN_NUM,3,0,0);
//Set CLK to FIO0.
AddRequest(lngHandle, LJ_ioPUT_CONFIG, LJ_chSPI_CLK_PIN_NUM,0,0,0);
//Set CS to FIO1.
AddRequest(lngHandle, LJ_ioPUT_CONFIG, LJ_chSPI_CS_PIN_NUM,1,0,0);
//Execute the configuration requests.
GoOne(lngHandle);
Following is pseudocode to do the actual SPI communication:
//Transfer the data.
eGet(lngHandle, LJ_ioSPI_COMMUNICATION, 0, &numBytesToTransfer, array);
4.3.11 - I²C Serial Communication
The UE9 supports Inter-Integrated Circuit (I²C or I2C) communication as the master only. I²C is a synchronous serial protocol
typically used to communicate with chips that support I²C as slave devices. Any 2 digital I/O lines are used for SDA and SCL. Note
that the I²C bus generally requires pull-up resistors of perhaps 4.7 kΩ from SDA to Vs and SCL to Vs, and also note that the screw
terminals labeled SDA and SCL (if present) are not used for I²C.
This serial link is not an alternative to the USB connection. Rather, the host application will write/read data to/from the UE9 over
USB, and the UE9 communicates with some other device using the serial protocol. Using this serial protocol is considered an
advanced topic. A good knowledge of the protocol is recommended, and a logic analyzer or oscilloscope might be needed for
troubleshooting.
There is one IOType used to write/read I²C data:
LJ_ioI2C_COMMUNICATION
The following are special channels used with the I²C IOType above:
LJ_chI2C_READ // Value= number of bytes (0-240). x1= array.
LJ_chI2C_WRITE // Value= number of bytes (0-240). x1= array.
LJ_chI2C_GET_ACKS
The following are special channels, used with the get/put config IOTypes, to configure various parameters related to the I²C bus.
See the low-level function description in Section 5.3.20 for more information about these parameters:
LJ_chI2C_ADDRESS_BYTE
LJ_chI2C_SCL_PIN_NUM // 0-22. Pull-up resistor usually required.
LJ_chI2C_SDA_PIN_NUM // 0-22. Pull-up resistor usually required.
LJ_chI2C_OPTIONS
LJ_chI2C_SPEED_ADJUST
The LJTick-DAC is an accessory from LabJack with an I²C 24C01C EEPROM chip. Following is example pseudocode to
configure I²C to talk to that chip:
//The AddressByte of the EEPROM on the LJTick-DAC is 0xA0 or decimal 160.
AddRequest(lngHandle, LJ_ioPUT_CONFIG, LJ_chI2C_ADDRESS_BYTE,160,0,0);
//SCL is FIO0
AddRequest(lngHandle, LJ_ioPUT_CONFIG, LJ_chI2C_SCL_PIN_NUM,0,0,0);
//SDA is FIO1
AddRequest(lngHandle, LJ_ioPUT_CONFIG, LJ_chI2C_SDA_PIN_NUM,1,0,0);
//See description of low-level I2C function.
AddRequest(lngHandle, LJ_ioPUT_CONFIG, LJ_chI2C_OPTIONS,0,0,0);
//See description of low-level I2C function. 0 is max speed of about 150 kHz.
AddRequest(lngHandle, LJ_ioPUT_CONFIG, LJ_chI2C_SPEED_ADJUST,0,0,0);
//Execute the configuration requests.
GoOne(lngHandle);
To Next Page
Loading...