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Adding a USB port to a product has now become almost essential – particularly if that product is required to interface to a PC or laptop. Whilst many economy devices developed with 8-bit micros may not have easy access to an integrated USB device port, there are a number of solutions on the market that overcome this issue. |
These solutions often come in the form of a USB bridge device such as those from FTDI Chip’s reknowned FT-X series. These simple function devices offer a bridge between a USB host PC and a variety of standard interfaces found on most embedded MCUs or ASICs such as UART, I2C or FIFO. |
The FT-X series has been optimised to provide the ultimate in power, price and packaging performance. |
Device |
FT200XD |
FT201X |
FT220X |
FT221X |
FT230X |
FT231X |
FT234XD |
FT240X |
Description |
USB to I2C slave interface |
USB to I2C slave interface |
USB to 4-Bit SPI / FT1248 interface |
USB to 4-Bit SPI / FT1248 interface |
USB to basic UART |
USB to full handshake UART |
USB to basic UART |
USB to parallel FIFO interface |
Data Rates |
3.4Mbit/s |
3.4Mbit/s |
500kbyte/s |
1MByte/s |
3MBaud |
3MBaud |
3MBaud |
1MByte/s |
CBUS Pins |
1 |
6 |
1 |
1 |
4 |
4 |
1 |
2 |
Packages |
10-Pin DFN |
16-pin QFN 16-pin SSOP |
16-pin QFN 16-pin SSOP |
20-pin QFN 20-pin SSOP |
16-pin QFN 16-pin SSOP |
20-pin QFN 20-pin SSOP |
12-pin DFN |
20-pin QFN 20-pin SSOP |
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All devices are USB 2.0 full speed compliant and benefit from 512 bytes internal data buffers (RX/TX), 1.8V-3.3V IO, and a typical 8mA operational power consumption |
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USB TO RS232 Design Example |
The simplest and most common use of FTDI Chip devices is for the purpose of bridging USB ports to a UART peripheral interface. |
The UART interface may operate at 1.8V to 5V in which case it is possible to realize the design with only one IC such as the FT231X which will handle all the protocol translation on chip. |
If the design is connecting to either RS232, RS422, RS485 then the design will require an additional transceiver to convert the FT231X UART signals to the appropriate levels. |
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TTL |
UART |
RS232 |
RS422 |
RS485 |
Signal Swing |
0v to 3V3/5V |
+/-5V to +/-15V |
+/-2V |
+/-1.5V |
Termination |
Single Ended |
Single Ended |
Differential |
Differential |
Transmission length |
~2m |
~15m |
~1200m |
~1200m |
No of transmitters /receivers on a line |
1 Driver 1 Receiver |
1 Driver 1 Receiver |
1 Driver 10 Receiver |
32 Driver 32 Receiver |
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It is possible for the design to simply use RXD and TXD signals but with FTDI Chip solutions, the option to implement full modem control is also provided. |
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Delivering the best in USB to UART, FIFO and I2C interfacing, the FT-X series will be extending soon. Sign up to our newsletter here to be the first to find out more! |
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