I’ve designed a custom RTK Facet PCB by combining three boards into one—mainboard, display board, and connector board—eliminating PCB connectors in the process. The PCB is fully assembled, but I’m facing an issue where the USB port is not showing up when trying to program or install firmware.
I’ve already tried: Changing the data cable Installing the correct CH340 drivers
I suspect it might be a hardware issue. If anyone with embedded systems experience could help review and troubleshoot, I’d really appreciate it!
Your assistance means a lot to me. You can also view the entire project by giving your easyEDA username, which will add you to the team. This way, you can easily see which specific components I used in this project to learn & help in this regard. @TS-Russell@sparky It meant a lot to me that I could reach you personally via LinkedIn or email for assistance.
You need to check if the USB Hub is working correctly. Does it appear in the Device Manager when you connect your board? You should see an extra “Generic USB Hub” appear under “Universal Serial Bus controllers”.
Please check the SCL and SDA jumpers on the Hub chip:
They should be open:
They allow you to connect an I2C EEPROM to the Hub chip, to store the VID, PID etc.. You can not connect them to a normal I2C bus.
Dear @PaulZC Yes, I have checked every USB-related sections in device manager. Additionally, does your suggestion mean there is not any major problem in the schematic I have provided and I must strictly disconnect SCL and SDA jumpers on the Hub chip? The USB hub chip “USB2512B-I/M2” should be checked or replaced if it still does not work. Is that the correct solution?
I don’t have time to study your schematic in detail. And I don’t want to join EasyEDA to look at your design. All I can do is take a quick look at the documents you share openly and comment on the things that ‘jump out at me’.
My advice would be to start fault-finding on the soft power switch. You need to get that working first.
Do you have a battery connected? Or just USB?
What voltage do you see on V_BATT, V_USB and V_RAW?
Is the soft power switch working? What voltage do you see on V_VOUT? Did you press the POWER_BTN?
Is ESP_3V3 3.3V?
The peripheral 3.3V may not yet be 3.3V because you do not yet have code on the ESP32 to enable the regulator.
Have you added enough decoupling capacitors? The SparkFun Facet needs more decoupling capacitors too…!
Then you can start fault-finding on the USB Hub.
Have you checked for continuity of the USB_DM and USB_DP signals? All the way from the USB-C connector to the USB2512 IC?
Have you checked for shorts?
On the PCB, did you route DM and DP as a 90 Ohm differential pair?
Do you have good grounding? Did you use a ground plane? Is your PCB 4-layer, or only 2?
Is V_USB 5.0V?
Is VBUS_DET 2.5V?
What voltage do you see on the XTALOUT and XTAL IN pins? An oscilloscope will help.
Are you sure SJ2 and SJ3 are open? On the schematic, it appears you have traces shorting them closed. SDA and SCL on the USB2512 must be left open.
Then, once the USB Hub is working and appears as a “Generic USB Hub”, you can start to fault-find the ESP32 and the CH340.
Please check DTR# and RST#. They look reversed. RST# should be named RTS# (Ready To Send). RST usually means ReSeT.
@PaulZC Can I get the BOM file so that I can buy the exact component used in the latest RTK facet? It would be helpful if I chose the wrong components, as many of them have multiple options. This led to the completion of my study project.
The Eagle design files are available on GitHub. You can use the Eagle BOM tool to view the BOM for each board. If there are any individual components you need help with, let us know.
Changing the data cable
