Vu 8 Channel LiDAR Module, 48°/0.3°, USB, CAN Bus, RS485 & UART - User Manual

Table Of Contents
LeddarVu User Guide Page 58 of 129
The SPI clock frequency can be in the range between 500 kHz and 25 MHz.
5.1.4.4. Access
To access a parameter, you need to add a parameter offset to the associated bank start base
address. Use the parameter length to get or set the whole parameter field.
5.1.4.5. Modification
To modify a parameter:
1. Disable the write protection of the module by sending the write enabled command.
2. Poll the status register to get the ready state and write enabled flag asserted.
3. Send the new parameter value.
4. Poll the status register to get the ready state.
5. Send the write disabled command (write protection) to prevent any unwanted parameter
change.
NOTE: To prevent any data corruption or loss after modifying a parameter or a firmware update,
the module must be in the ready state before shutting it down or doing a hard reset.
5.2. I2C Interface
The I2C interface on the SPI board is a direct link to the receiver and source modules. For the
moment, only the temperature sensor is accessible. Refer to the LM75BIMM-3/NOPB temperature
sensor datasheet from Texas Instruments.
The I2C interface available with the enhance board is a port connected to MCU but not implemented
for the moment.
5.3. USB Interface
The USB interface available with the USB, CAN and SERIAL board is a VCP (virtual COM port)
serial emulation port. This port is used as a serial link with the Modbus protocol (refer to Section
5.4 Serial Link Interface). This interface can also be used to update the USB, CAN and SERIAL
board firmware in the bootloader mode.
5.4. Serial Link Interface
The serial links can be of the following electric signals: TTL, RS-232, RS-422, and RS-485.
The serial link ports use the Modbus protocol using the RTU transmission mode only. This section
describes the commands that are implemented.
For more information on the Modbus protocol, please visit www.modbus.org.
Read input register (function code 0x4)
The following table presents the registers for the read input commands.