3. A Tour of the SerDes Hardware

Before learning how to configure and set up the device, let’s examine the device from all sides to understand all of its interfaces and status indicators.

3.1. Block Diagram

3.2. Label and Status Indicators

3.2.1. LED Indicators

Status LEDs are located on either end of the device and provide indicators of the SerDes link and power state.

FPD-Link III Status LEDs (STP side)

LED

Description

RED

Power

Enabled when the device has power. This will be enabled with either PoC or external power supply.

YELLOW

FPD-Link III PASS status

Configured via register on DS90UB954-Q1.

GREEN

FPD-Link III LOCK status

Configured via register on DS90UB954-Q1.

GMSL2 Status LEDs (Coax side)

LED

Description

RED

PoC Power

Enabled when power-over-coax is present.

YELLOW

GMSL2 ERRB status

Configured via register on MAX9295.

GREEN

GMSL2 LOCK status

Configured via register on MAX9295.

3.3. Connector Interfaces

3.3.1. External 3.3V I2C Bus Header

Although I2C access is available over the SerDes link, an external header is provided to allow connection of an additional 3.3V I2C master. All internal SerDes chips can be accessed using this header for configuration or status monitoring. Register descriptions and control information can be found in the SerDes part datasheets. This interface should be compatible with any I2C controller or adapter that operates at 3.3V.

Note

This header is compatible with the TI USB2ANY adapter using the Analog Launchpad software, and also the Teensy uC using the Maxim GMSL GUI. For more information, see the adapter documentation.

3.3.2. STP Ports

Two input STP ports are available that connect to the FPD-Link III deserializer.

3.3.3. Coax Port: FAKRA

A single output coax port is available that connects to the GMSL2 serializer.

3.3.4. External Power Supply: 4-40V:

3.3.5. Dip Switch Configuration

External switches are available to set various configuration parameters for the SerDes chips. The switches can be used to select between multiple options for the I2C addresses and SerDes link modes. Switches are ON when toggled down, and OFF when toggled up.

Configuration values are captured at power up, but can generally be changed later using I2C registers on the SerDes chip. For more information, see the SerDes part documentation.

Switch	Description
1	GMSL2 I2C Address (CFG0 pin) SW1=OFF (0x80) SW1=ON (0xC4)
2/3	GMSL2 Mode (CFG1 pin) SW2/SW3=OFF/ON (GMSL2 6Gbps) SW2/SW3=ON/OFF (GMSL2 3Gbps) SW2/SW3=ON/ON (GMSL1 HIM) (Not supported on REV1.0)
4	FPD-Link III I2C Address (IDX pin) SW4=OFF (0x60) SW4=ON (0x70)
5/6	FPD-Link III Mode (MODE pin) SW5/SW6=OFF/ON (CSI2 nonsynchronous) SW5/SW6=ON/OFF (RAW10) SW5/SW6=ON/ON (CSI2 synchronous)
7	Power-over-STP Enable (Not supported on all versions)

3.4. Mapped GPIO

GPIO signals are internally mapped between the SerDes parts to allow control and status signals to propagate along the link. Examples of signals include frame sync or sensor resets. Use of the GPIO must be configured properly in the SerDes parts. For more information, see the SerDes part documentation.

DS90UB954-Q1	MAX9295
GPIO0	CNTL0/MFP8
GPIO1	CNTL1/MFP4
GPIO2	CNTL2/MFP3
GPIO3	CNTL3/MFP0
GPIO4	CNTL4/MFP7
GPIO5	MFP5
GPIO6	MFP6