I have designed the following FT232H circuitry into a board on which I require a USB to I2C interface:
This circuit largely comes from the schematic for the UM232H eval kit (which I have and it works) and the Adafruit FT232H Breakout board:
https://ftdichip.com/wp-content/uploads/2020/07/DS_UM232H.pdf
https://learn.adafruit.com/assets/88382
I am using a bus powered configuration, so VREGIN is the USB 5V and VCCD is the 3.3V output. For some reason, however, whenever I plug the USB cable into my PC running Windows 10, I get the following error:
I followed the procedures FTDI provides in their driver installation guide (https://ftdichip.com/wp-content/uploads/2022/05/AN_396-FTDI-Drivers-Installation-Guide-for-Windows-10_11.pdf), but I still see this error. I suspect a hardware issue but I have not been able to find the problem. I have confirmed that "VBUS" is approximately 5V, "3V3" is approximately 3.3V, and "VCCCORE" is approximately 1.8V. Have I missed something? I realize I have to tie ADBUS2 to ADBUS1, but that wouldn't explain why the PC isn't recognizing the device.
EDIT: I have confirmed that VCCA does not show any voltage. According to the datasheet I expected to see 1.8V:
EDIT 2: I have also already referred to a number of threads here, most notably this one:
USB device not recognized
I looked the USB device up using the Device Manager and it has not gotten to the point of recognizing the VID/PID. The error I am seeing is "Device Descriptor Request Failed":
Best Answer
The FT232H chip is a USB2 high-speed (480Mbps) device. You however are using 27R/47pF filter on DP/DM wires. You cannot do this. "USB full-speed compatible" means that the FT232 device will respond to FS host traffic if the host is FS and will ignore chirping negotiations. But you cannot suppress chip-K from FT232H, and since your host is HS, it will chirp back and end the link in HS terminated state and will start 480Mbps signaling, and this signal will be severely crippled by your RC filter. Remove C2 C3 and use zero ohm in R6/R7 places, and everything will work fine. See for details this answer: https://electronics.stackexchange.com/a/311591/117785