Description: This is a breakout board for the SP3485 RS-485 transceiver IC, which will convert a UART serial 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. This board requires a very low amount of power and can operate from a single +3.3VDC supply.
This breakout board includes the SP3485 RS-485 transceiver, filter capacitor, and other components shown on the schematic. We’ve broken out the RS-485 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.
Based on 5 ratings:
3 of 7 found this helpful:
Although it is reasonably priced and possessed of a clever variety of plated holes for the attachment of various connectors, if I had done my homework I would not have purchased this board. Why? Because the obscure SP3485 chip that it uses does not have automatic flow control and is therefore not compatible with many popular open source libraries for RS485 and in particular Modbus RTU.
Unfortunately there don’t seem to be a lot of other choices except certain parts in online auctions and building one’s own board with MAX488, MAX13487E or another flow-control transceiver.
So this board delivers what it promises, but what it promises is a clever implementation of a chip that no one else uses for quite good reasons. Not recommended.
0 of 1 found this helpful:
I should not have to load up Eagle to get a correct schematic and layout of the board. The Schematic file should be complete
You are looking at a PDF of the Eagle schematic. It is not incomplete, it simply makes use of hidden connections that are managed within Eagle. The easiest way to view the traces is in Eagle. We post the PDF and the Eagle files so that the end user has the option to view as either. However, for best experience, using Eagle to view the schematic allows quicker and simpler navigation through the wiring.
Worked fine in my application. I needed to replace the C grade part with an E grade part for wider temperature range. The C grade part will be fine for most applications. It was nice to be able to simply swap out the part.
The SparkFun Transceiver Breakout - RS-485 ships configured so that are in receive only mode until you pull the RTS pin high. When RTS is high, they go into transmit mode and will return to receive mode once RTS is low again. While in transmit mode, the board will not be able to receive any data from the RS-485 bus.