How do you connect multiple MCP39F501 devices in an RS485 Bus?

The MCP39F501 should use a full duplex RS485 transceiver (two RS485 links). The RE (Receiver output Enable) and DE (Driver output Enable) pins should not be tied together. The RE of the transceiver should always be enabled and the DE should be tied to the DIR pin.

In this case, all the device should receive is the command from the master (PC). However, only the node that matches the address sent should enable its driver and allow it to send data to the master (PC). The RX RS485 link should be connected in parallel with the other RX485 link and connected to the driver of RS485 of the master. The driver RS485 link should also be connected in parallel with the other driver RS485 and connected to the RX of RS485 of the driver. This should eliminate bus collisions.

© 2024 Microchip Technology, Inc.
Notice: ARM and Cortex are the registered trademarks of ARM Limited in the EU and other countries.
Information contained on this site regarding device applications and the like is provided only for your convenience and may be superseded by updates. It is your responsibility to ensure that your application meets with your specifications. MICROCHIP MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND WHETHER EXPRESS OR IMPLIED, WRITTEN OR ORAL, STATUTORY OR OTHERWISE, RELATED TO THE INFORMATION, INCLUDING BUT NOT LIMITED TO ITS CONDITION, QUALITY, PERFORMANCE, MERCHANTABILITY OR FITNESS FOR PURPOSE. Microchip disclaims all liability arising from this information and its use. Use of Microchip devices in life support and/or safety applications is entirely at the buyer's risk, and the buyer agrees to defend, indemnify and hold harmless Microchip from any and all damages, claims, suits, or expenses resulting from such use. No licenses are conveyed, implicitly or otherwise, under any Microchip intellectual property rights.