SparkFun USB to RS-485 Converter

This is the latest revision and addresses issues with the previous board. This breakout board connects an SP3485 RS-485 transceiver with an FT232RL USB UART IC to convert a USB stream into RS-485. The SP3485 is a half-duplex transceiver, meaning it can only communicate in one direction, but it can achieve transmission speeds of up to 10 Mbps.

The TXDEN pin of the FT232RL is connected to the transmit and receive port. Activating the inputs of the SP3485 will use this line to control the transmission mode of the RS-485 transceiver. With the correct drivers installed, the FT232RL will be listed as a virtual COM port; drivers are available for Windows, Mac, and Linux.

This breakout board includes LEDs for SP3485, FT232, TX/RX/RTS, a mini-B USB port, filter capacitors, and other components tailored to the schematic. We have broken out the RS485 output to three different connections: (1) an RJ-45 connector, (2) a 3-pin 3.5 mm screw terminal, and (3) a 3-pin 0.1" header; none of these outputs are populated.

Features:

* Fully equipped with SP3485 RS-485 transceiver and FT232RL USB UART IC
* Operates via USB power supply
* RX, TX, and RTS LED indicators
* Mini-B USB port
* USB power supply and RX/TX lines are broken out to a 0.1-inch header.
* RS-485 input/output broken out to RJ-45 connector, 3.5 mm screw terminal, and 0.1" grid header
* Driver/receiver enable connected to the RTS line of FT232RL
* -7V to +12V common mode input voltage range

Dimensions: 1.55 x 0.9 inches.