Frequently Asked Questions

Q. How to detect when enumeration has completed via hardware?
A.

Most FTDI devices use a PWREN# signal. It will be high (power = off) under the following conditions: -The device is in reset OR -The device is not yet configured by USB enumeration, or the USB enumeration sequence has failed OR -The host PC system is in the USB suspend state

Q. Does the FT260 provide a Virtual COM Port over HID class?
A.

The FT260 does not present a Virtual Com Port on the host PC. The device is a HID class device rather than an FTDI Vendor Class device and therefore does not require the FTDI drivers to be loaded. The LibFT260 library provided by FTDI can be used by an application to control the UART, GPIO and I2C Master functions of the device. The FT260 can also be interfaced using HID requests directly from the application.

Q. With the latest drivers two sets are supplied for i386 and AMD64. For Win 64 and Intel processor should we be using the i386 drivers?
A.

Drivers should be installed automatically (by Windows). If you choose to do this manually, if you specify the higher level folder and choose to search sub-directories it should be chosen automatically.

So you shouldn’t need to specify the exact driver files.

The architecture is named after AMD because AMD invented it, with the Athlon 64. Similarly, the 32-bit i386 architecture is named after Intel’s 386 processor, because it was the first of its kind, but i386 will also work on AMD processors.

Even if you have an intel CPU, AMD64 is what you’d use to install 64-bit on your computer (it uses the same instruction sets).

Q. What is the maximum SPI clock rate when using FT4222H?
A.

The maximum SPI interface operating clock can be set up to 40MHz in master mode and 20MHz in slave mode. The SPI clock rate is subject to system clock and the SPI clock_div.

Q. How can I submit my driver for certification?
A.

Microsoft® instituted a device driver certification process to ensure the drivers are functional with their products. Many FTDI customers are interested in changing the FTDI drivers to reflect their corporate identity. This can be done via editing FTDI’s INF files, however, once an INF file has been edited, its original digital signature is no longer valid and needs to be certified. Please see AN_101: Submitting Modified FTDI Drivers for Windows Hardware Certification for a guide on the certification. Please note that Microsoft may update their process and should be supported by Microsoft.

Q. What external EEPROM is recommended for use with the FTDI USB Hi-Speed ICs?
A.

For the FT2232H and FT4232H, a 93C46, 93C56 or 93C66 is recommended. The FT232H requires the 93C56 or 93C66. All of these serial EEPROMs need to be specified or configured for 16-bit word and 3.3V I/O operation. There are many manufacturers of this type of device, and FTDI does not have a preference.