Document No.: FT_000061
FT2232H DUAL HIGH SPEED USB TO MULTIPURPOSE UART/FIFO IC
Datasheet Version 2.09
Clearance No.: FTDI#77
3.4.6 FT2232H Pins used as a Fast Serial Interface
The FT2232H channel B can be configured for use with high-speed optical bi-directional isolated serial
data transfer: Fast Serial Interface. (Not available on channel A). A proprietary FTDI protocol designed to
allow galvanic isolated devices to communicate synchronously with the FT2232H using just 4 signal wires
(over two dual opto-isolators), and two power lines. The peripheral circuitry controls the data transfer
rate in both directions, whilst maintaining full data integrity. Maximum USB full speed data rates can be
achieved. Both „A‟ and „B‟ channels can communicate over the same 4 wire interface if desired.
When configured in this mode, the pins used and the descriptions of the signals are shown in
Channel B
Pin No.
38
Name
Type
Fast Serial Interface Configuration
Description
Fast serial data input.
Fast serial clock input.
FSDI
INPUT
39
FSCLK
INPUT
Clock input to FT2232H chip to clock data in
or out.
Fast serial data output.
Fast serial Clear To Send signal output.
40
FSDO
OUTPUT
41
FSCTS
OUTPUT
Driven low to indicate that the chip is ready
to send data
Table 3.9 Channel B Fast Serial Interface Configured Pin Descriptions
For a functional description of this mode, please refer to section 4.8 Fast Opto-Isolated Serial Interface
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