1 Typical Applications
 Automotive
 Single chip USB to four channels UART (RS232, RS422 or RS485) or Bit-Bang interfaces.
 Single chip USB to 2 JTAG channels plus 2 UARTS.
 Single chip USB to 1 JTAG channel plus 3 UARTS.
 Single chip USB to 1 SPI channel plus 3 UARTS.
 Single chip USB to 2 SPI channels plus 2 UARTS.
 Single chip USB to 2 Bit-Bang channels plus 2 UARTS.
 Single chip USB to 1 SPI channel, plus 1 JTAG channel plus 2 UARTS.
 Single chip USB to 2 I2C channels plus 2 UARTS.
 Numerous combinations of 4 channels.
 Upgrading Legacy Peripheral Designs to USB
 Field Upgradable USB Products
 Cellular and cordless phone USB data transfer cables and interfaces.
 Interfacing MCU / PLD / FPGA based designs to USB
 PDA to USB data transfer
 USB Smart Card Readers
 USB Instrumentation
 USB Industrial Control
 USB MP3 Player Interface
 USB FLASH Card Reader / Writers
 Set Top Box PC - USB interface
 USB Digital Camera Interface
 USB Bar Code Readers
4 Function Description
The FT4232HA is FTDI’s 5th generation of USB devices. The FT4232HA is a USB 2.0 High Speed (480Mb/s) to UART/MPSSE IC that is automotive qualified for AEC temperature grade 2. It has the capability of being configured in a variety of industry standard serial interfaces.
The FT4232HA has four independent configurable interfaces. Two of these interfaces can be configured as UART, JTAG, SPI, I2C or bit-bang mode, using an MPSSE, with independent baud rate generators. The remaining two interfaces can be configured as UART or bit-bang.
4.1 Key Features
USB High Speed to Quad Interface. The FT4232HA is a USB 2.0 High Speed (480Mbits/s) to four independent flexible/configurable serial interfaces.
Functional Integration. The FT4232HA integrates a USB protocol engine which controls the physical Universal Transceiver Macrocell Interface (UTMI) and handles all aspects of the USB 2.0 High Speed interface. The FT4232HA includes an integrated +1.2V Low Drop-Out (LDO) regulator and 12MHz to 480MHz PLL. It also includes 2kbytes Tx and Rx data buffers per channel. The FT4232HA effectively integrates the entire USB protocol on a chip.
MPSSE. Multi-Purpose Synchronous Serial Engines (MPSSE), capable of speeds up to 30 Mbits/s, provides flexible synchronous interface configurations.
Data Transfer Rate. The FT4232HA supports a data transfer rate up to 12 Mbit/s when configured as an RS232/RS422/RS485 UART interface. Please note the FT4232HA does not support the baud rates of 7 Mbaud, 9 Mbaud, 10 Mbaud and 11 Mbaud.
Latency Timer. This is used as a timeout to flush short packets of data back to the PC. The default is 16ms, but it can be altered between 2ms and 255ms. Lower values may reduce latency but may also increase USB bandwidth usage and reduce efficiency.
4.2 Functional Blocks Description
Quad Multi-Purpose UART/MPSSE Controllers. The FT4232HA has four independent UART/MPSSE Controllers. These blocks control the UART data or control the Bit-Bang mode if selected by the SETUP command. The blocks used on channel A and channel B also contain a MPSSE (Multi-Protocol Synchronous Serial Engine) in each of them which can be used independently of each other and the remaining UART channels. Using this it can be configured under software command to have 1 MPSSE + 3 UARTS (each UART can be set to Bit Bang mode to gain extra I/O if required) or 2 MPSSE + 2 UARTS.
USB Protocol Engine and FIFO control. The USB Protocol Engine controls and manages the interface between the UTMI PHY and the FIFOs of the chip. It also handles power management and the USB protocol specification.
Dual Port FIFO TX Buffer (2Kbytes per channel). Data from the Host PC is stored in these buffers to be used by the Multi-purpose UART/FIFO controllers. This is controlled by the USB Protocol Engine and FIFO control block.
Dual Port FIFO RX Buffer (2Kbytes per channel). Data from the Multi-purpose UART/FIFO controllers is stored in these blocks to be sent back to the Host PC when requested. This is controlled by the USB Protocol Engine and FIFO control block.
RESET Generator - The integrated Reset Generator Cell provides a reliable power-on reset to the device internal circuitry at power up. The RESET# input pin allows an external device to reset the FT4232HA. RESET# should be tied to VCCIO (+3.3v) if not being used.
Independent Baud Rate Generators - The Baud Rate Generators provides an x16 or an x10 clock input to the UART’s from a 120MHz reference clock and consists of a 14 bit pre-scaler and 4 register bits which provide fine tuning of the baud rate (used to divide by a number plus a fraction). This determines the Baud Rate of the UART which is programmable from 183 baud to 12 million baud. The FT4232HA does not support the baud rates of 7 Mbaud, 9 Mbaud, 10 Mbaud and 11 Mbaud.