FT232RL — USB 2.0 to Full-Handshake UART Interface IC

Overview

The FT232RL is an iconic USB-to-serial UART interface IC manufactured by FTDI (Future Technology Devices International). As one of the most famous chips in USB peripheral history, it converts USB 2.0 signals into asynchronous serial UART data with full hardware handshaking lines.

Featuring an internal integrated clock oscillator (eliminating external crystals), 128-byte internal EEPROM for custom USB Vendor ID (VID), Product ID (PID), and serial strings, and CBUS multi-function GPIO pins (for LED status indicators), the FT232RL supports baud rates from 300 bps to 3 Mbps at TTL signal levels.

Quick reference


USB Specification	USB 2.0 Full-Speed ( $12\text{ Mbps}$ )
Supply Voltage (`VCC`)	3.3 V to 5.25 V DC
Internal LDO Regulator	$3.3\text{ V}$ DC ( $50\text{ mA}$ max output on 3V3OUT pin)
Max Baud Rate	$3.0\text{ Mbps}$ (RS-422 / RS-485 / TTL logic)
Internal EEPROM	128 Bytes (Stores custom VID, PID, Product Name, Serial Number)
Clock Source	Integrated Internal Clock Generator (No external crystal needed)
Buffer Sizes	128-byte Receive Buffer, 256-byte Transmit Buffer
Package	28-pin SSOP / 32-pin QFN

Pinout (SSOP-28 Package)

text

             ┌───┴───┐
       TXD  1│ 1   28│ OSCO (NC)
       DTR  2│       │27 OSCI (NC)
       RTS  3│       │26 TEST (GND)
     VCCIO  4│ FT232 │25 AGND
        RXD 5│   RL  │24 NC
       RI   6│       │23 CBUS0 (TXLED)
       GND  7│       │22 CBUS1 (RXLED)
        NC  8│       │21 GND
       DSR  9│       │20 VCC (+5V)
       DCD 10│       │19 RESET (VCC)
       CTS 11│       │18 CBUS2
     CBUS4 12│       │17 3V3OUT (3.3V Out)
       SSD 13│       │16 USBDM (D-)
     USBDP 14│       │15 USBDM / USBDP
             └───────┘

Pin	Name	Type	Description
1	`TXD`	Output	Transmit Asynchronous Data Output (Connect to MCU RXD)
2	`DTR`	Output	Data Terminal Ready Handshake Line (Used for Arduino Auto-Reset)
3	`RTS`	Output	Request to Send Control Line
4	`VCCIO`	Power	Power supply pin for UART I/O pins (+1.8V to +5.25V DC)
5	`RXD`	Input	Receive Asynchronous Data Input (Connect to MCU TXD)
7	`GND`	Power	Ground reference (0 V)
15	`USBDM`	I/O	USB D- Differential Data Line
16	`USBDP`	I/O	USB D+ Differential Data Line
17	`3V3OUT`	Output	3.3V Internal LDO Regulator Output (Requires 0.1µF decoupling cap)
20	`VCC`	Power	Main Power Supply (+4.0V to +5.25V DC)
22	`CBUS1`	I/O	Multi-function Configurable Pin 1 (Default RX LED Drive)
23	`CBUS0`	I/O	Multi-function Configurable Pin 0 (Default TX LED Drive)

Arduino Uno / Pro Mini Auto-Reset Circuit