Alignment issue on ESP32-S2 Thing Plus

[flupke]

Starting from Example2-DMXInput and after finding this comment I changed the example to dmxSerial(1) and enPin = 3 and started receiving values from my DMX controller.

However the values read on channel 1 was changing constantly in a seemingly random way.

I tried to display 192 channels with this code from another comment in the same issue:

#include <SparkFunDMX.h>

SparkFunDMX dmx;
HardwareSerial dmxSerial(1);
uint8_t enPin = 3;
uint16_t numChannels = 192;

void setup()
{
    Serial.begin(115200);
    Serial.println("SparkFun DMX Example 2 - Input");

    dmxSerial.begin(DMX_BAUD, DMX_FORMAT);
    dmx.begin(dmxSerial, enPin, numChannels);
    dmx.setComDir(DMX_READ_DIR);

    Serial.println("DMX initialized!");
}

void loop()
{
    while(dmx.dataAvailable() == false)
    {
        dmx.update();
    }

    uint8_t data[numChannels];
    dmx.readBytes(data, numChannels, 1);

    for (int i=0; i < numChannels; i++) {
      if (i%32 == 0) {
        Serial.printf("\n(%3d)   ", i+1);
      }

      Serial.printf("%3d ", data[i]);
    }
    Serial.printf("\n");

    delay(1000);
}

I see values are "shifted" after each read, for example look at how the 134 89 22 sequence moves around between two reads:

  1)     0   0   0   0   0   0   0   0   0   0 255 255 160 244   0   0   0   0   0   0   0   0   0   0   0   0 255 255 160 244   0   0 
( 33)     0   0   0   0   0   0   0   0   0   0 255 255 160 244   0   0   0   0   0   0   0   0   0   0   0   0 255 255 160 244   0   0 
( 65)     0   0   0   0   0   0   0   0   0   0 255 255 160 244   0   0   0   0   0   0   0   0   0   0   0   0 255 255 160 244   0   0 
( 97)     0   0   0   0   0   0   0   0   0   0 255 255 160 244   0   0   0   0   0   0   0   0   0   0   0   0 255 255 160 244   0   0 
(129)     0   0   0   0   0   0   0   0   0   0   0   0   0 255 247   0 134  89  22   0   0   0   0   0   0   0   0   0 255 255 160 244 
(161)     0   0   0   0   0   0   0   0   0   0   0   0 255 255 160 244   0   0   0   0   0   0   0   0   0   0   0   0 255 255 160 244 

(  1)     0   0   0   0   0   0   0   0   0   0 255 255 160 244   0   0   0   0   0   0   0   0   0   0   0   0 255 255 160 244   0   0 
( 33)     0   0   0   0   0   0   0   0   0   0 255 255 160 244   0   0   0   0   0   0   0   0   0   0   0   0 255 255 160   0 255 255 
( 65)   160 244   0   0   0   0   0   0   0   0   0   0   0   0 255 255 160 244   0   0   0   0   0   0   0   0   0   0   0   0   0   0 
( 97)     0 255 247   0 134  89  22   0   0   0   0   0   0   0   0   0 255 255 160 244   0   0   0   0   0   0   0   0   0   0   0   0 
(129)   255 255 160 244   0   0   0   0   0   0   0   0   0   0   0   0 255 255 160 244   0   0   0   0   0   0   0   0   0   0   0   0 
(161)   255 255 160 244   0   0   0   0   0   0   0   0   0   0   0   0 255 255 160 244   0   0   0   0   0   0   0   0   0   0   0   0 

Does that ring a bell?

[sfe-SparkFro]

Hi there, apologies for the long response time!

This looks like a synchronization issue, which is probably caused by the large percentage of zeros sent by your controller. Could you please try removing the delay from your loop()? I suspect dmx.update(); isn't being called frequently enough, causing the RX buffer to be overflowed by a random amount before dmx.update(); is called again.