Description: This is the newest revision and fixes issues with the last board. This breakout board pairs an SP3485 RS-485 transceiver with an FT232RL USB UART IC to convert a USB stream to RS-485. The SP3485 is a half-duplex transceiver, so it can only communicate one way at a time, but it can reach transmission speeds of up to 10Mbps.
The TXDEN pin of the FT232RL is connected to the transmit and receive enable inputs of the SP3485, this line is used to control the transmission mode of the RS-485 transceiver. With the proper drivers installed, the FT232RL will enumerate as a virtual COM port; the drivers are available for Windows, Mac and Linux.
This breakout board includes the SP3485, FT232, TX/RX/RTS LEDs, Mini-B USB connector, filter capacitors, and other components shown on the schematic. We’ve broken out the RS485 output to three different connections: (1) an RJ-45 connector, (2) a 3-pin 3.55mm screw terminal, and (3) a 3-pin 0.1" pitch header; none of these output connectors come populated.
Dimensions: 1.55x0.9 inches
Based on 3 ratings:
Simple. Straightforward. Just hook it up per the pinout and go. Add a RJ45 and make it easier.
I bought 10 Pc. Three of the units work ok. Seven of them do not work.
I have checked the converters with an oscilloscope and a multimeter. In the bad pieces, level of Rx pin of the SP3485 is low, and when data arrives goes to high without following the incoming data. Resistance between Vcc and Rx pins is infinite. In the good pieces, level of Rx pin is high, and when data arrives follows data correctly. Resistance between Vcc and Rx pins is high, but not infinite.
I wait for your comments Regards Daniel
Hmm, this is not an issue we’ve seen before. I’ll do some testing on some boards, and contact you directly to resolve this for you.
The description states “Driver/Receiver Enable connected to RTS line of FT232RL” but the schematic shows that the driver receiver/receiver enable is connected to TXDEN. Which is it?