3.4 Hardware Reference

Mechanical Installation

The RDK IMU core board has one 2×7 pin header and four mounting holes. It connects to the 2×7 socket on the carrier board and can be secured with four M2.5×11 standoffs and screws, or a custom support structure. Core board dimensions (unit: mm):

The carrier board has one 2×7 socket and four mounting holes for the core board, plus one 40-pin socket and three mounting holes for the development board. It can be secured with three M2.5×11 standoffs and screws, or a custom support structure. Carrier board dimensions (unit: mm):

Hardware Interface Reference

Topology

The diagram below shows the hardware topology between the RDK IMU Module and an RDK development board.

Component List

Ref	Component
1	2.54 mm, 2×20P socket
2	2.54 mm, 3×5P pin header
3	2.54 mm, 2×7P pin header & socket
4	0603 LED R/G/B
5	YS-SBZ9650DYB05
6	DS18B20

Interface Description

① 40-Pin Header

This interface connects to the development board 40-pin header and is the only link between the IMU module and the board.
Pin 1 matches the RDK X5 definition. Pin assignment:

Desc	Name	Pin	Pin	Name	Desc
	3V3	1	2	5V
Used for SPI/I2C	SDA/SDI	3	4	5V
Used for SPI/I2C	SCL/SCK	5	6	N/A
	N/A	7	8	N/A
Ground	GND	9	10	N/A
	LED	11	12	N/A
	LED	13	14	N/A
	LED	15	16	N/A
	3V3	17	18	N/A
Used for SPI/I2C	SDA/SDI	19	20	N/A
Used for SPI	SDO	21	22	N/A
Used for SPI/I2C	SCL/SCK	23	24	CS_ACCEL	Used for SPI
Ground	GND	25	26	CS_GYRO	Used for SPI
	N/A	27	28	N/A
	N/A	29	30	N/A
	BUZZ	31	32	N/A
	N/A	33	34	N/A
	N/A	35	36	INT1	Used for Interrupt
Connect DS18B20	DQ	37	38	INT3	Used for Interrupt
	GND	39	40	N/A

② Communication Mode Selector

Use this interface to switch the module communication mode. Connect the center 5-pin header to the five pins labeled I2C with jumper caps to select I2C, as shown:

Connect the center 5-pin header to the five pins labeled SPI to select SPI, as shown:

③ IMU Core Board Connector

Connects the IMU core board to the carrier board.

④ Indicator LEDs

The carrier board has three LEDs for status indication, driven via 40-pin GPIO.

⑤ Buzzer

The carrier board has an active buzzer for status indication.

⑥ Temperature Sensor

The carrier board includes a DS18B20 temperature sensor on the 1-Wire bus for ambient or carrier board temperature measurement.