1. Device Overview & Purpose:

️· The FT231X is a USB to full handshake serial UART interface device.
️· It simplifies USB implementations and reduces component count through integrated features.
️· Designed to efficiently utilize USB bandwidth.

2. Key Features:

️· Functional Integration: Includes an MTP memory (for configuration), clock generation, power management (AVCC filtering, POR, LDO regulators).
️· Configurable CBUS I/O: The 4 CBUS pins can be configured with various functions (see table below).
️· Bit Bang Mode: Supports asynchronous bit bang mode with read (RD#) and write (WR#) strobes.
️· Synchronous Bit Bang Mode: Allows synchronous data transfer.
️· Power Management: Operates on 3.3V - 5.25V with low power consumption in USB suspend mode (125µA).
️· UART Level Conversion: Supports UART logic from 1.8V to 3.3V (5V tolerant).

3. CBUS Configuration Options (Table from Datasheet):

CBUS Signal Option	Description
TRI-STATE	Tri-states the I/O pad
DRIVE 1	Outputs a constant high
DRIVE 0	Outputs a constant low
TXDEN	Enables transmit data for RS485
PWREN#	Output to control external power (used for Power-On-Reset)
TXLED#	Pulses low when transmitting data
RXLED#	Pulses low when receiving data
TX&RXLED#	Pulses low when transmitting/receiving
SLEEP#	Goes low during USB suspend
CLK24MHz	24 MHz Clock output (suspended during USB suspend)
CLK12MHz	12 MHz Clock output (suspended during USB suspend)
CLK6MHz	6 MHz Clock output (suspended during USB suspend)
GPIO	Allows the pins to be used as general purpose I/O.
BCD Charger	Indicates when a charger is connected
BCD Charger#	Inverse of BCD Charger
BitBang_WR#	WR# Strobe Output for bit bang mode
BitBang_RD#	RD# Strobe Output for bit bang mode
VBUS Sense	Detects the presence of VBUS
Time Stamp	Indicates USB SOF reception
Keep_Awake#	Prevents device from entering suspend state

4. Key Functional Blocks (Briefly):

️· MTP Memory: Stores device configuration.
️· Clock Generation: Provides timing signals.
️· Power Management: Regulates voltage and current.
️· UART Interface: Handles serial communication.
️· Bit Bang I/O: Enables custom data transfer modes.

Important Notes from the Text:

️· Application Notes are available on the FTDI website ([www.ftdichip.com](http://www.ftdichip.com/)) for more detailed information on Bit Bang modes (AN232R-01) and other features.
️· The clock outputs (CLK24MHz, CLK12MHz, CLK6MHz) are suspended during USB suspend mode.