Document No.: FT_000061
FT2232H DUAL HIGH SPEED USB TO MULTIPURPOSE UART/FIFO IC
Version 2.21
Clearance No.: FTDI#77
4.11 RS232 UART Mode LED Interface Description
When configured in UART mode the FT2232H has two IO pins on each channel dedicated to controlling
LED status indicators, one for transmitted data the other for received data. When data is being
transmitted / received the respective pins drive from tri-state to low in order to provide indication on the
LED‟s of data transfer. A digital one-shot timer is used so that even a small percentage of data transfer is
visible to the end user.
VCCIO
TX
RX
220R
220R
FT2232H
TXLED#
RXLED#
Figure 4.21 Dual LED UART Configuration
Figure 4.21 shows a configuration using two individual LED‟s – one for transmitted data the other for
received data.
VCCIO
LED
220R
FT2232H
TXLED#
RXLED#
Figure 4.22 Single LED UART Configuration
In Figure 4.22 the transmit and receive LED indicators are wire-OR‟ed together to give a single LED
indicator which indicates any transmit or receive data activity.
Note that the LED‟s are connected to the same supply as VCCIO.
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