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philibertc / micronova_controller

Allows you to easily control via MQTT any Micronova equiped pellet stove. (MCZ, Extraflame, Laminox, and many others brands!)
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Why the use of the enable RX #39

Closed netdata-be closed 2 years ago

netdata-be commented 2 years ago

I'm wondering why you choose to use a GPIO to enable the RX from the 1wire RS232? I would be interested to know the reason behind this.

philibertc commented 2 years ago

Hello, image If you don't use the "enable RX" the RX optocoupler (in the middle) will act as a pullup as soon as you try to use the TX (at the bottom) : when the TX pin is set to GND, the current can pass from the other side (from pin 4 to 3) to GND and in the process allow the current to pass through the optocoupler in the middle, which will act as a pullup. The Stove_Serial pin therefore never makes the low signal. This is one of the problems of half-duplex serial (on a single cable). I hope my explanation is clear,

Best Regards, Philibert