Product Description

Table Of Contents

2. Inter-Integrated Circuit (I2C)

This section specifies the I2C interface and the I2C bootloader which enables communication between the X4

and an external host for transfer of radar and configuration data. The X4 I2C interface supports a maximum

clock frequency of 400 kHz and the default device 7-bit slave address is 0x5A.

2.1. I2C Specification

UnitMaxMinParameter

kHz400Maximum I2C clock frequency

0x5A7-bit I2C slave address

Table 2.1. I2C Specification

2.2. I2C Commands

After boot, the X4 will by default enable the I2C bootloader. This bootloader can be used to upload program

data to the internal memory of the X4.Typically, this program will be a sensor profile provided by Novelda which

configures the sensor and enables signal processing.When the host has completed the transfer of the program

to the X4´s internal memory, it must initiate a soft reset to start executing the uploaded program. The profile

may implement its own I2C commands in addition to the ones described below.

Note that the memory in the X4 is not retained through a power cycle or when the Enable pin is pulled low.

After such events, the host must upload the program data through the bootloader again.

This section will describe the protocol used by the bootloader.

2.2.1.Writing commands and data

All bytes written to the X4 I2C device are stored in IDATA (0x80 to 0xFF). All bytes written in the same transaction

are stored consecutively and processed after the next STOP condition on the I2C bus. The core I2C function-

ality processes the following commands:

Byte #2Byte #1Byte #0LengthCommand

0x001NOP

Address (LSB)Address (MSB)0x013Set data pointer

Data[0]Data length0x023 + NWrite data

0x031Soft reboot

0x38: stationary0x042Data pointer control

0x39: auto-increment

(default)

Table 2.2. I2C Bootloader Commands

2.2.2. Reading data

When the master reads data, the X4 slave device will respond with the byte at the current data pointer address

in SRAM, then increment the data pointer address if configured to do so.

TBD-2020

Page 5 of 13

Rev. C - Advance

X4C007 - Datasheet