RFLink via Ethernet - solution

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RFLink via Ethernet - solution

#1 Post by klassisch » 15 Aug 2020, 07:31


RFLink is a great project and I am using it on my ioBroker System.
The required USB connection may become a disatvantage in some cases, forcing the antenna close to the location of the server.
USB extensions might be a solution but Ethernet could be a better solution in many cases.

I modified a Mega2560 an a Mini Mega2560 (both CH340) to use a USRIOT Module such as
- USR-TCP232-T2 (tested) - attention 3.3V digital I/O
- USR-K7 (to be tested) - attention 3.3V digital I/O
- USR-TCP232-E2 (to be tested) - attention 3.3V digital I/O

- USR-TCP232-306 (tested)
- USR-TCP232-410S (tested)

The original USRIOT units worked for me, a "clone" did not for me.
USRIOT offers a free virtual COM-driver for their devices so that I could replace the USB-COM by an other COM-port number addressing the virtual COM driver which connects to the TCP-module.
Normal operation works very wenn, while flashing over Eth does not work.
So the modification has to contain a switch to enable flashing over USB.
The standard setup of the serial interface to USB within a Mega260 is shown here
RFLink-Eth-instead-USB-standard.jpg (76.1 KiB) Viewed 13733 times
This has to be modified in the serial read line to switch between Ethernet module during normal operation and USB for flashing (if new RFLInk Firmware would be available)
RFLink-Eth-instead-USB-Ethernet.jpg (91.82 KiB) Viewed 13733 times
The modification can be done by removing the resistor between the Atmega's read input and the serial <-> USB converter such as CH340 and connecting to the switch.

Using e.g. USR-TCP232-T2, USR-K7, USR-TCP232-E2 level shifters between the 5V Mega-signal and the 3.3V USR signals have to be used. The cheap ones, using a MOSFet, do the job.

Here a proof of concept of a RFLInk-Mega2560 with a RRS232 interface to be connected to an USR device such as USR-TCP232-302, TCP232-306, USR-TCP232-410S
RFLink-Ethernet-6x4-P1350729.JPG (200.97 KiB) Viewed 13733 times
RFLink-Ethernet-6x4-P1350702.JPG (102.75 KiB) Viewed 13733 times
RFLink-Ethernet-6x4-P1350707.JPG (110.7 KiB) Viewed 13733 times

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