Hello all!  I am working on a PCB design (open source here, the FT232H is on page 3) which uses an FT232H to provide USB to SPI/I2C/UART conversion.  I've been testing the first board for some time, and have been unable to get any response out of the FT232H chip.  I see that it's outputting power on the VPHY and VPLL pins, but it has not been responsive over the USB interface -- both USB pins seem to be stuck floating.

The elephant in the room with my design is that I didn't provide an EEPROM for the FT232H, since the datasheet indicates it's not required (this board will only be used internally and I don't need to use a custom VID/PID or any permanent configuration).  However, I couldn't find any examples whatsoever of how to connect the EEPROM pins when there isn't an EEPROM on the board, so I wasn't entirely sure what to do.  Originally I tried pulling EEDATA low, and then I tried reworking the board to pull all three EEPROM pins high, but neither seemed to produce a response.

Things I have tried so far:

• Pulling pin 31 (ACBUS7/PWRSAV#) high in case the chip is in sleep mode (even though the datasheet indicates that this function is disabled without an EEPROM
• Replacing the chip on the board
• Pulling all the EEPROM pins high
• Cutting the traces from the internal USB hub and bodge soldering on a USB cable direct to my PC (so I can rule out the internal hub)
• Measuring voltages on every pin.  I don't remember the exact results but there was nothing that seemed abnormal (except that, when I had the pulldown on EEDATA, it was at like 0.4V
• Attaching a 1Ghz logic analyzer to the USB traces.  Did not observe any activity other than the host device trying fruitlessly to reset the FT232H

After all this, I'm about out of ideas.  Does anyone know if there's anything special I need to do to get the FT232H to work without an EEPROM attached?  Are there any other troubleshooting steps I can do to diagnose the issue?  I'm just about to give up and redesign with a competitor chip (CY7C65211), so any tips would be appreciated!

Thank You very much

Hello,

Our devices can't simulate regular flash memory.

Best Regards,
FTDI Community

And the second question, please. Can we implement a compound USB device using FTDI 600 and Dx200 or Dx300? One function will be regular file memory (like regular flash memory), and the second will be information conversion. We have implemented the second part. I'm interested in the first function. Can your device (ftdi) simulate regular flash memory. Thank you.

Thank you, Mister. We will make a decision and I will write to you. Moreover, we are going to change FTDI 200 to FTDI 600. But this, I think, does not make the problem go away

Hello,

Unfortunately the FTDI driver source is confidential so there is no documentation on it apart from the D2XX Programmer’s Guide.

If you wanted to write your own kernel based driver then we could provide an NDA to give you access to the API for FTxxxx Devices.

The USB Host Controller would need to implement FTDI drivers. This is not an easy task.

Please note that we can only provide a table of the USB transfers under NDA (API for FTxxxx Devices) and unfortunately we cannot provide source code samples or support for writing drivers on a particular OS.

Is a table of USB requirement sufficient for your needs?
It requires previous hands on writing USB driver experience for your particular MCU/OS and requires extensive USB knowledge.
It's a difficult task and we don’t provide support for it.

Please contact your local support team for the NDA form.

The other route you may want to explore is LibFTDI which is an open source library/driver but is not created/supported by FTDI:

https://www.intra2net.com/en/developer/libftdi/

This third party solution already includes the source so may suit you if you as the driver source is also supplied and may give you more options.

Best Regards,
FTDI Community

Hello,

Unfortunately this is not something that we have any experience with.

Other FTDI community users may be able to help.

Best Regards,
FTDI Community

Hello everybody. I'm new to the FTDI community.
We have a controller that communicates with the computer via FTDI. We use the D2XX interface functions from the user mode program to communicate with the FTDI driver (device). Now I want to use the FTDI device from kernel mode (Windows), but we don't have any documentation related to the FTDI driver. Please tell me where to find or buy it. Thank you.

Yes, I know that the FT232 and FT245 can only be opened once. They provide a handle once opened.
This is why I only open it once and save the handle in shared memory so that other programs use it for read and write functions, but it doesn't work. I also have the same problem with the VCP driver

Hello,

When using the D2xx driver it can only be accessed by one handle at a time.

Note that FT245B is Not Recommended for New Designs (NRND) and is being made EOL.
See AN_559 Migrating from FT2xxB however the same limitation applies with the D2xx driver.

There could be other FTDI Community members who have experience with sharing a handle in shared memory but it's not something that FTDI support.

Best Regards,
FTDI Community