Help diagnosing MAX485 problems

I am using a MAX485 board wired to an ESP32.

RO - Pin 16 on ESP32 (U2_RXD)
RE - Ground
DE - Ground
DI - NOTHING

VCC - +5v (Separate supply, but ground shared with ESP32)
B - DMX
A - DMX
GND - Ground

I am using simple code from githubbhttps://github.com/luksal/ESP32-DMX-RX

#include <dmx.h>

int readcycle = 0;

void setup() {
  Serial.begin(115200);
  DMX::Initialize();
}

void loop()
{
  if(millis() - readcycle > 1000)
  {
    readcycle = millis();

    Serial.print(readcycle);
      
    if(DMX::IsHealthy())
    {
      Serial.print(": ok - ");
    }
    else
    {
      Serial.print(": fail - ");
    }
    Serial.print(DMX::Read(1));
    Serial.print(" - ");
    Serial.print(DMX::Read(110));
    Serial.print(" - ");
    Serial.println(DMX::Read(256));
  }
}

I am getting zero data received.

Output:-

16:36:54.837 → 4746742: fail - 0 - 0 - 0
16:36:55.826 → 4747743: fail - 0 - 0 - 0
16:36:56.844 → 4748744: fail - 0 - 0 - 0
16:36:57.840 → 4749745: fail - 0 - 0 - 0
16:36:58.824 → 4750746: fail - 0 - 0 - 0
16:36:59.844 → 4751747: fail - 0 - 0 - 0
16:37:00.841 → 4752748: fail - 0 - 0 - 0
16:37:01.824 → 4753749: fail - 0 - 0 - 0
16:37:02.841 → 4754750: fail - 0 - 0 - 0
16:37:03.833 → 4755751: fail - 0 - 0 - 0
16:37:04.855 → 4756752: fail - 0 - 0 - 0
16:37:05.850 → 4757753: fail - 0 - 0 - 0
16:37:06.835 → 4758754: fail - 0 - 0 - 0
16:37:07.851 → 4759755: fail - 0 - 0 - 0
16:37:08.833 → 4760756: fail - 0 - 0 - 0
16:37:09.849 → 4761757: fail - 0 - 0 - 0
16:37:10.833 → 4762758: fail - 0 - 0 - 0
16:37:11.854 → 4763759: fail - 0 - 0 - 0

Freestyler shows data leaving on Address 1.
DMX bus has terminator.

I have used this MAX485 chip previously with a UNO and it worked ok.

I have a power LED on the MAX485.

Suggestions on troubleshooting further as I am lost :frowning:

RO - Pin 16 on ESP32 (U2_RXD)

is the UART on that pin, or is it used for SPI/I2C?

Do you mean the default serial connection via USB?

I presume not as the code writes to serial for output, it would never work if it’s also reading on that port. I thinks that’s pin 39/40.

Only just got this board, so I could be wrong.