DS_FT311D USB ANDROID HOST IC Datasheet
Version 1.2
Document No.: FT_000660 Clearance No.: FTDI# 305
5 Peripheral Interfaces
In addition to the USB Host, FT311D contains the following peripheral interfaces:
General Purpose Input Output (GPIO)
Universal Asynchronous Receiver Transmitter (UART)
Four Pulse Width Modulation blocks (PWM)
I2C Master
Serial Peripheral Interface (SPI) Slave
Serial Peripheral Interface (SPI) Master
Note: Only one interface may be selected at any time.
The modes are selected by setting the CNFGx pins.
The following sections describe each peripheral in detail.
5.1 General Purpose Input Output
FT311D provides up to 7 configurable Input/Output pins. All pins are independently configurable to be
either inputs or outputs.
5.2 UART Interface
When the peripheral interface is configured in UART mode, the interface implements a standard
asynchronous serial UART port with flow control, for example RS232/422/485. The UART can support
baud rates from 300 baud to 6 Mbaud.
Data transfer uses NRZ (Non-Return to Zero) data format consisting of 1 start bit, 7 or 8 data bits, an
optional parity bit, and one or two stop bits. When transmitting the data bits, the least significant bit is
transmitted first. Transmit and receive waveforms are illustrated in Figure 5-1 and Figure 5-2:
Figure 5-1 UART Receive Waveform
Figure 5-2 UART Transmit Waveform
Baud rate (default =9600 baud), flow control settings (default = RTS/CTS), number of data bits
(default=8), parity (default is no parity) and number of stop bits (default=1) are all configurable from the
Android application. Please refer to
http://www.ftdichip.com/Support/Documents/ProgramGuides/FT31XD_Android_programmer_guide(FT_0
00532).pdf for further details.
uart_tx_active is transmit enable, this output may be used in RS485 designs to control the transmit of
the line driver.
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