working principle

The main chip RTL8367RB-VB-CG (hereinafter referred to as "8367 chip") is one of the network management chips launched by REALTEK. The chip can provide 5 layer 2 network management ports, 2 10/100/1000M switch controllers and 1 51-core hardware resources.

This project mainly uses five of the layer 2 network management ports, and only involves configuring the self-test status of the chip when it is powered on and reset on the hardware.

effect

Design and develop a configuration-free 5-port 1000base Ethernet switch using the 5 layer 2 network management ports of the 8367 chip. Provide appropriate power to the board, and the board will work normally and enable five Ethernet devices to communicate with each other.

working conditions

Power supply:

1. According to the working range recommended in the chip manual, as shown below, in order to facilitate voltage reduction, only two voltages, 3.3V and 1.1V, are selected as the power supply voltages for the chip.
2. The general power supply voltage is not directly 3.3V, so we chose the commonly used USB power supply method of 5V to supply power to the board from outside the board, and then step down the 5V to 3.3V and 3.3V to 3.3V inside the board. 1.1V design.

Temperature:

1. The recommended working range in the above figure includes the working environment temperature 0-70℃.

Test parameters

The Ethernet switch produced in this project was used to connect to the home network, and the network speed was tested, and it basically matched the speed of the package.

Debugging experience

1. Be sure to read the chip's datasheet carefully, including pin ordering, pin attributes, and which configuration pins are forced to input high or input ground;
2. Because the chip used in this project has a digital ground pad under the belly, but I did not add pad vias on the digital ground pad when I created the new package. Manual soldering is a bit difficult. Readers need to choose the welding method according to their own conditions;
3. During the subsequent debugging process, it was found that the power consumption of the 8367 chip is relatively large, and the heat generated by the 8367 chip and LDO is still a little, so you can consider adding a cooling fan interface or directly using the backup round hole connector as the power supply interface for the fan.

Debugging experience

1. Two-color LED speed indication design

According to the two-color LED solution in the manual , I designed the two-color light on the RJ-45 network port this time. What I understand is that LED2 is for Gigabit speed, and LED1 is for 100M and below. When powered on, the LED1 and LED2 inputs are high, and then when the network port is connected for speed judgment: when a gigabit device is connected, LED2 is low, LED1 is high, and then the green light should be on, but in fact it is on orange. Colored lights, so the Gigabit and Hundred Mbit LEDs should be LED1 and LED2 respectively .

2. LDO

Power requirements of 8367 chip

According to this table, two typical power supplies are selected: 3.3V and 1.1V .

Typical applications of 1117-3.3 chips

The actual application is basically the same as the typical application in the manual

Typical applications of VRH1102LTX chip

The actual application is basically the same as the typical application in the manual

When debugging the trial switch, I found that the heat generated by several LDOs was relatively large. It was estimated that the current of the power supply was not derated enough and was approaching the limit of the LDO chip.

There is also a problem with the cooperation between the housing designed in the PCB file and the TYPE-C interface. After installing the housing and connecting the type-C , I found that the DEMO board cannot provide power.

Currently, these three areas of DEMO have not been properly handled, but other functions can still be implemented. You can modify and modify it on this basis.

Demo video

https://www.bilibili.com/video/BV1Nt4y1g77M?share_source=copy_web&vd_source=a4283f7f60b4b27cf4bc52ead7cb0382