FT221X USB to 8-bit SPI (FT1248 Bridge)

Download the FT221X USB to 8-bit SPI (FT1248 Bridge) driver here. By serving as a compact bridge, this USB2.0 Full Speed IC facilitates seamless communication between 8-Bit SPI/FT1248 links. Operating at speeds of up to 1MByte/s, this device, functioning as an FT1248 slave, ensures effective data transfer while consuming minimal power (8mA).

FT221X USB to 8-bit SPI (FT1248 Bridge)

The FT221X, comes with the complete feature set of the FT-X series. It makes it easy to combine the USB into system designs through the FT1248 link. Likewise with its easy to use design and compatibility. In addition it enables fast and easy  addition of USB functionality into various applications. The FT1248 link is also found on the FT220X USB to 4-Bit SPI which also makes use of the FT1248 Bridge.

FT221X USB to 8-bit SPI (FT1248 Bridge)8-bit SPI

The 8-bit SPI, or Serial Peripheral link , is a communication protocol commonly used to connect microcontrollers and other devices. It allows for the exchange of data in an 8-bit format, enabling easy and synchronized data transmission between devices with minimal overhead. See also the FT201X Full Speed USB to I2C Bridge Driver on this website.

FT1248 interface

The FT1248 link is a flexible serial parallel link that supports 8-bit data transfer. It enables an effective communication between devices by giving synchronized and data exchange in both directions.

FT1248 Bridge

The FT1248 bridge is a compact link that acts as a bridge between different devices using the FT1248 protocol. It helps in making an easy and dependable communication by changing data from the FT1248 format to a another format.

Hardware Features

The FT1248 serial parallel link offers flexibility in 1, 2, 4, or 8 bit wide modes. Likewise resembling an SPI slave in 1 bit mode. It seamlessly handles the entire USB protocol without the need for USB-specific firmware programming. The link integrates a 2048 byte Multi-Time-Programmable (MTP) Memory. Additionally enabling the storage of device descriptors and CBUS I/O configuration within the chip.

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One notable feature is the fully integrated clock generation, eliminating the requirement for an external crystal. Additionally, users have the option to select clock output, providing a convenient link to external MCUs or FPGAs without the need for additional components. This seamless integration simplifies system design and reduces complexity.

Data Transfer

With data transfer rates of up to 1MByte/s, the FT1248 link ensures effective and high-speed communication. The inclusion of a 512 byte receive buffer and 512 byte transmit buffer, along with buffer smoothing technology, further improves data throughput, allowing for smooth and uninterrupted data transfer.

FTDI’s Virtual Com Port (VCP) and Direct (D2XX) drivers are provided royalty-free, eliminating the need for USB driver development in most cases. This significantly reduces development time and effort, enabling faster implementation of USB functionality in various applications.

The link also offers a configurable CBUS I/O pin, providing flexibility for customizing the links input/output configuration according to specific requirements. Additionally, the device is supplied pre-programmed with a unique USB serial number, ensuring device identification and enabling seamless integration into USB systems.


Likewise support for bus powered, self-powered, and high-power bus powered USB configurations further expands the links suitability and adaptability. The integrated +3.3V level converter simplifies USB I/O connectivity, allowing seamless communication between the link and USB devices.

The FT1248 link ensures dependable and compatible operation with its true 3.3V CMOS drive output and TTL input. It can operate down to 1.8V with external pull-ups, allowing various voltage levels. The link also includes configurable I/O pin output drive strength, giving options in driving other devices.

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Battery Charger Detection is another valuable feature, particularly for mobile devices. It enables the link to detect the presence of a charger on the USB port, helping higher current flow and faster charging of batteries.

Integrated power-on-reset circuitry ensures proper initialization and reliable operation of the link. The internal 3.3V/1.8V Low Dropout (LDO) regulators assist in stable and effective power management.

With a low operating current of 8mA (typical) and USB suspend current of 125uA (typical), the FT1248 link maintains effective power without affecting performance. It also uses minimal USB bandwidth, optimizing the overall USB system’s performance.

The link is compatible with UHCI/OHCI/EHCI host controllers, ensuring seamless integration and compatibility with a wide range of USB host systems. With USB 2.0 Full Speed compatibility, the FT1248 link meets the industry-standard USB specifications, ensuring reliable and effective data transfer between devices.

Operating within a temperature range of -40°C to 85°C, the link is designed to endure extreme conditions. It is available in 20 Pin SSOP and QFN packages. Likewise both meeting standards of the Restriction of Hazardous Substances (RoHS) rules, making it an green friendly design and production methods.

Application Use

Enabling battery charging at higher current for faster charge times. Likewise the USB to SPI interface operates in 1-bit mode and includes dedicated charger port (DCP) detection. Additionally see also the FT200XD Full Speed USB to I2C Bridge Driver on here as well as the CP2102 USB to UART Bridge Driver.

D2XX Direct Drivers

Windows (Desktop) 2021-07-15

FT221X Driver X86 (64-Bit)

FT221X Driver X86 (32-Bit)

Windows RT Driver (ARM) (2014-07-04)

Linux X64 (64-Bit) / X86 (32-Bit)  (2020-05-18)


VCP Drivers

Windows (Desktop) 2021-07-15

FT221X Driver X86 (64-Bit)

FT221X Driver X86 (32-Bit)