05-01-2023, 08:16 AM
For anyone having the same problem: it was possible to read messages by putting a 2k resistor between pins 2 and 5 of the onboard SP485EE (i.e. a pulldown on the receive enable pin), but then the receive circuit of the SP485EE is always active, which means that the ESP32 also receives the bytes that it sends itself (a sort of local echo). That may be acceptable when you write your own firmware, but ESPhome - for instance - can't handle this. (Not out of the box, anyway.)
The real solution:
KinCony immediately sent me two MAX13487 ICs. I've put one on the board, replacing the SP485EE, and now I can send AND receive messages (without the local echo). I am happy that, once the problem was identified, KinCony offered a solution right away. Thanks! :-)
That being said, the conspicuous silence I received when asked how the wrong chip ended up on the board in the first place does not fill me with confidence about production and/or quality control; I am left wondering how many boards are out there with the same problem, and how many people are spending hours figuring out "why it doesn't work"...
The real solution:
KinCony immediately sent me two MAX13487 ICs. I've put one on the board, replacing the SP485EE, and now I can send AND receive messages (without the local echo). I am happy that, once the problem was identified, KinCony offered a solution right away. Thanks! :-)
That being said, the conspicuous silence I received when asked how the wrong chip ended up on the board in the first place does not fill me with confidence about production and/or quality control; I am left wondering how many boards are out there with the same problem, and how many people are spending hours figuring out "why it doesn't work"...