ESP32S2 I2S Parallel Output Issue

[techtoys]

IDE: Arduino IDE2.2.1
NeoPixelBus version 2.7.6
MCU: ESP32S2 WROVER-I

I am trying to drive x8 strips with ESP32S2 I2S. Before that, I have verified the hardware with one strip below:

#include <NeoPixelBus.h>

NeoPixelBus<NeoGrbFeature, NeoEsp32I2s0X8Ws2812xMethod> strip1(24, 42);

void setup() {
    Serial.begin(115200);
    delay(500);

    Serial.println();
    Serial.println("Initializing...");
    Serial.flush();

    // must call begin on all the strips
    strip1.Begin();
    Serial.println();
    Serial.println("Running...");
}

void loop() {
    delay(1000);
    // draw on the strips
    strip1.ClearTo(RgbColor(0, 0, 128));  //blue
    strip1.Show();

    delay(1000);
    strip1.ClearTo(RgbColor(128, 0, 0));  //red
    strip1.Show();
    Serial.println("Running...");
}

Code above worked as expected with strip1 flashed blue and red in alternate.
Now I add more strips with new code below:

#include <NeoPixelBus.h>

NeoPixelBus<NeoGrbFeature, NeoEsp32I2s0X8Ws2812xMethod> strip1(24, 42);
//new code
NeoPixelBus<NeoGrbFeature, NeoEsp32I2s0X8Ws2812xMethod> strip2(24, 41);
NeoPixelBus<NeoGrbFeature, NeoEsp32I2s0X8Ws2812xMethod> strip3(24, 40);
NeoPixelBus<NeoGrbFeature, NeoEsp32I2s0X8Ws2812xMethod> strip4(24, 39);
NeoPixelBus<NeoGrbFeature, NeoEsp32I2s0X8Ws2812xMethod> strip5(24, 38);
NeoPixelBus<NeoGrbFeature, NeoEsp32I2s0X8Ws2812xMethod> strip6(24, 37);
NeoPixelBus<NeoGrbFeature, NeoEsp32I2s0X8Ws2812xMethod> strip7(24, 36);
NeoPixelBus<NeoGrbFeature, NeoEsp32I2s0X8Ws2812xMethod> strip8(24, 35);


void setup() {
    Serial.begin(115200);
    delay(500);

    Serial.println();
    Serial.println("Initializing...");
    Serial.flush();

    // must call begin on all the strips
    strip1.Begin();
   //new code
    strip2.Begin();
    strip3.Begin();
    strip4.Begin();
    strip5.Begin();
    strip6.Begin();
    strip7.Begin();
    strip8.Begin();

    Serial.println();
    Serial.println("Running...");
}

void loop() {
    delay(1000);
    // draw on the strips
    strip1.ClearTo(RgbColor(0, 0, 128));  //blue
    strip1.Show();

    delay(1000);
    strip1.ClearTo(RgbColor(128, 0, 0));  //red
    strip1.Show();
    Serial.println("Running...");
}

Please notice that I am not running any code for strip2-strip8 in loop().

This time, strip1 is now showing any color. The main loop is printing periodic messages Running... that means the program is hanging up. But why there is no more color on strip1 ?

What may go wrong?

John

[Makuna]

You must call show on ALL channels before it will send the data. It's a single action to send all 8 channels, so every time a show on a channel is called, it registers that it is ready but waits until the last one is called before actually sending the data.
Updated Wiki to mention this detail.

[techtoys]

Yes, it works with a function to update all channels:

void UpdateAll(void){
    strip1.Show();
    strip2.Show();
    strip3.Show();
    strip4.Show();
    strip5.Show();
    strip6.Show();
    strip7.Show();
    strip8.Show();
}

[Makuna]

Glad it works for you.

Maybe longer term there should be a ShowAll(). I will think about that. I have been thinking about a Multibus object already for mapping all to act like one. Lots to consider.