FT221XQ-R International Semiconductor Technologies, FT221XQ-R Datasheet - Page 30

• Manufacturer Part Number: FT221XQ-R
• Description: Specifications: Applications: * ; Interface: * ; Voltage - Supply: 3.3 V ~ 5 V ; Package / Case: 20-VFQFN Exposed Pad ; Packaging: Digi-Reel
• Manufacturer: International Semiconductor Technologies

FT221X USB 8-BIT SPI/FT1248 IC Datasheet
Version 1.2
Document No.: FT_000630 Clearance No.: FTDI# 263
8
Application Examples
The following sections illustrate possible applications of the FT221X. The illustrations have omitted pin
numbers for ease of understanding since the pins differ between the FT221XS and FT221XQ package
options.
8.1 USB to FT1248 Converter
Figure 8.1 Application Example showing USB to FT1248 host
NOTE: ALL IO LINES SHOULD HAVE A 10k PULL UP TO VCCIO
The FT1248 can be used with 1-bit, 2-bit, 4-bit or 8-bit wide data. The Figure 8.1 is showing 8 bit mode.
By using 8 data bits you need fewer clock cycles to get the data across.
The FT221X is the slave device and the external FPGA/MCU is the bus master. The FT221X will auto
detect the bus width from the initial command byte sent by the controller. If not using all 8 data lines the
pins may be left unterminated as an internal pull-up ensures the device detects a logic 1.
Timing diagrams for 8-bit accesses can be seen in figures 8.2 and 8.3. For further information on the
mode see AN_167 FT1248 Basics from the FTDI website.
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