SparkFun USB to RS-485 Converter

SparkFun's USB to RS-485 Converter is a high-quality breakout board that integrates an SP3485 RS-485 transceiver with an FT232RL USB UART IC to transform a USB stream to RS-485. The SP3485 transceiver operates in half-duplex mode, allowing for one-way communication, but can achieve transmission speeds of up to 10Mbps.

The FT232RL's TXDEN pin is linked to the transmit and receive enable inputs of the SP3485. This connection controls the transmission mode of the RS-485 transceiver. When the appropriate drivers are installed, the FT232RL will be recognized as a virtual COM port. These drivers are compatible with Windows, Mac and Linux.

The breakout board comes with the SP3485, FT232, TX/RX/RTS LEDs, Mini-B USB connector, filter capacitors, and other components indicated in the schematic. The RS-485 output is broken out to three different connections: an RJ-45 connector, a 3-pin 3.55mm screw terminal, and a 3-pin 2.54mm pitch header. Please note, these output connectors are not pre-populated.

Key features of the SparkFun USB to RS-485 Converter include:

• Integration of SP3485 RS-485 transceiver and FT232RL USB UART IC
• USB power supply operation
• Presence of RX, TX, and RTS LED indicators
• Inclusion of a Mini-B USB connector
• USB power and RX/TX lines broken out to a 2.54mm pitch header
• RS-485 input/output broken out to RJ-45 connector, 3.5mm screw terminal, and 2.54mm pitch header
• Driver/Receiver Enable connected to RTS line of FT232RL
• -7V to +12V Common-Mode Input Voltage Range
• Dimensions: 3.94cm x 2.29cm

For more detailed information, SparkFun provides a range of useful documents, including a schematic, Eagle files, SP3485 datasheet, FT232RL VCP drivers, and a GitHub repository.