<![CDATA[COMMU design/scematic error]]>

<![CDATA[COMMU design/scematic error]]>The RS485 interface design for the COMMU appears to be wrong. As shown, the transmit data (TXD) is used to enable/disable the driver on the DE/RE pins, while the driver data input, DI is permanently strapped low.

This means that sending data will drive a 'one' or float the line, but never drive a 'zero'.

The correct implementation should be TXD connected to the DI pin and a third signal used to control the DE/RE pins.

Since there is no third signal available, this design is fundamentally broken and won't interoperate with my existing systems.

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]]>https://community.m5stack.com/topic/1414/commu-design-scematic-errorRSS for NodeWed, 22 Apr 2026 06:05:53 GMTTue, 22 Oct 2019 15:54:18 GMT60