EVAL232R FT232RL USB to RS232 Evaluation Module Datasheet Version 0.90

© Future Technology Devices International Ltd. 2005

Page 14

EEPROM. A high-power bus powered device must use this descriptor in the internal EEPROM to inform the

system of its power requirements.

v) For 3.3V power controlled circuits the VCCIO pin must not be powered down with the external circuitry (the

PWREN# signal gets its VCC supply from VCCIO). Either connect the power switch between the output of the

3.3V regulator and the external 3.3V logic or power VCCIO from the 3V3OUT pin of the FT232R.

6.4 LED Interface

The FT232RL’s CBUS0 and CBUS1 pins on the EVAL232R are configured to drive LED’s.

CBUS0 is used to indicate reception of data (RXLED#) and CBUS1 is used to indicate transmission of data (TXLED#).

When data is being transmitted or received the respective CBUS pin will drive from tri-state to low in order to provide

indication on the LEDs of data transfer. A digital one-shot time is used so that even a small percentage of data transfer

is visible to the end user.

The FT232R CBUS pins have 3 configurable options for driving an LED - these are TXLED#, RXLED#, and

TX&RXLED#.