RS485 not receiving anything

[victorclaessen]

Ok, I've examined the board. I've checked the pins of the RS485 ic (marked SP485EE 1435L B95770) with an oscilloscope. I can see incoming communication on pin 6 (RS485 A), but nothing on pin 1 (receiver output). I then checked pin 2 (Receiver output enable active LOW) and it is high (5V)!

I guess this is to be expected, this is also marked in the Kincony documentation (see below). But doesn't this mean that the SP485EE output is permanently disabled???

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UPDATE:

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Ok, if I pull down pin2 on the SP485EE, then suddenly esphome receives data from the UART (pin 16).

Code:

21:22:40    [D]    [uart_debug:114]    >>> 01 06 00 01 03 00 D8 FA
21:22:40    [V]    [modbus:042]    Modbus received Byte  1 (0X1)
21:22:40    [V]    [modbus:042]    Modbus received Byte  6 (0X6)
21:22:40    [V]    [modbus:042]    Modbus received Byte  0 (0X0)
21:22:40    [V]    [modbus:042]    Modbus received Byte  1 (0X1)
21:22:40    [V]    [modbus:042]    Modbus received Byte  3 (0X3)
21:22:40    [V]    [modbus:042]    Modbus received Byte  0 (0X0)
21:22:40    [V]    [modbus:042]    Modbus received Byte  216 (0Xd8)
21:22:40    [V]    [modbus:042]    Modbus received Byte  250 (0Xfa)
21:22:40    [V]    [modbus_controller:055]    Modbus response queued
21:22:40    [V]    [component:204]    Component modbus took a long time for an operation (0.06 s).
21:22:40    [V]    [component:205]    Components should block for at most 20-30ms.
21:22:40    [V]    [modbus_controller:063]    Process modbus response for address 0x0 size: 4
21:22:40    [V]    [modbus_controller:308]    Command ACK 0x1 259
21:22:41    [D]    [uart_debug:114]    <<< 01 06 00 01 03 00 D8 FA

I don't know, but this looks like a design problem?

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By the way, I have a revision 1.4 board. I notice that you have a 1.5 board. Did anything change on the RS485 side in between revisions?