SSD1306 doesn't work on ESP32?

Posted on Sat 4th, March 2017

• #1

Aifer

function go(){
//g.on();
// write some text
g.drawString("Hello World!",2,2);
// write to the screen
g.flip();
}

// SPI
SPI2.setup({sck:18, mosi:23});
var g = require("SSD1306").connectSPI(SPI2, 4 /DC/, 12 /RST/, go, { cs:5 });

no errors, but the OLED doesn't work.
• #2

Wilberforce

I believe the pins 2-6 are used for the flash chip, so best not to use pins 4 & 5.

Change those to say pins 16,17, rewire and see how you get on.

var g = require("SSD1306").connectSPI(SPI2, 16 /DC/, 12 /RST/, go, { cs:17 });

@JumJum - Should we add a warning if these pins are used?
• #3

Aifer
In SSD1306.js, connectSPI() has some codes not work well on ESP32, such as digitalPulse(rst,0,10), cs.reset() and cs.set() .

Just rewrite some lines:

cs.reset() --> digitalWrite(cs,0)
cs.set() --> digitalWrite(cs,1)
digitalPulse(rst,0,10) --> for(var i = 0; i<10; i++){ digitalWrite(rst,0); digitalWrite(rst,1); }
:-)

The OLED module works well.

But, the initial action of SPI and Graphics module must be in the onInit() function. why?
And the RST pin must be connected! The cs option must be defined too.
```
var g;

function start(){
    // write some text
    g.drawString("Hello Espruino!", 2, 2);
    // write to the screen
    g.flip();
}

function onInit(){
  SPI2.setup({sck:18, mosi:23});
  g = require("mySSD1306").connectSPI(SPI2, 16 /*DC*/, 12 /*RST*/, start, {cs:17});
}

save();
```

• #4

Aifer

mySSD1306.js

/* Copyright (c) 2014 Sam Sykes, Gordon Williams. See the file LICENSE for copying permission. */
/*
Module for the SSD1306 OLED controller in displays like the Crius CO-16

function go(){
 // write some text
 g.drawString("Hello World!",2,2);
 // write to the screen
 g.flip();
}
// I2C
I2C1.setup({scl:B6,sda:B7});

var g = require("SSD1306").connect(I2C1, go);
// or
var g = require("SSD1306").connect(I2C1, go, { address: 0x3C });

// SPI
var s = new SPI();
s.setup({mosi: B6, sck:B5});
var g = require("SSD1306").connectSPI(s, A8, B7, go);

*/
var C = {
 OLED_WIDTH                 : 128,
 OLED_CHAR                  : 0x40,
 OLED_CHUNK                 : 128
};

// commands sent when initialising the display
var extVcc=false; // if true, don't start charge pump
var initCmds = new Uint8Array([
             0xAe, // 0 disp off
             0xD5, // 1 clk div
             0x80, // 2 suggested ratio
             0xA8, 63, // 3 set multiplex, height-1
             0xD3,0x0, // 5 display offset
             0x40, // 7 start line
             0x8D, extVcc?0x10:0x14, // 8 charge pump
             0x20,0x0, // 10 memory mode
             0xA1, // 12 seg remap 1
             0xC8, // 13 comscandec
             0xDA, 0x12, // 14 set compins, height==64 ? 0x12:0x02,
             0x81, extVcc?0x9F:0xCF, // 16 set contrast
             0xD9, extVcc?0x22:0xF1, // 18 set precharge
             0xDb, 0x40, // 20 set vcom detect
             0xA4, // 22 display all on
             0xA6, // 23 display normal (non-inverted)
             0xAf // 24 disp on
            ]);
// commands sent when sending data to the display
var flipCmds = [
     0x21, // columns
     0, C.OLED_WIDTH-1,
     0x22, // pages
     0, 7 /* (height>>3)-1 */];
function update(options) {
  if (options) {
    if (options.height) {
      initCmds[4] = options.height-1;
      initCmds[15] = options.height==64 ? 0x12 : 0x02;
      flipCmds[5] = (options.height>>3)-1;
    }
    if (options.contrast!==undefined) initCmds[17] = options.contrast;
  }
}


exports.connect = function(i2c, callback, options) {
  update(options);
  var oled = Graphics.createArrayBuffer(C.OLED_WIDTH,initCmds[4]+1,1,{vertical_byte : true});

  var addr = 0x3C;
  if(options) {
    if (options.address) addr = options.address;
    // reset display if 'rst' is part of options
    if (options.rst) digitalPulse(options.rst, 0, 10);
  }

  setTimeout(function() {
    // configure the OLED
    initCmds.forEach(function(d) {i2c.writeTo(addr, [0,d]);});;
  }, 50);

  // if there is a callback, call it now(ish)
  if (callback !== undefined) setTimeout(callback, 100);

  // write to the screen
  oled.flip = function() {
    // set how the data is to be sent (whole screen)
    flipCmds.forEach(function(d) {i2c.writeTo(addr, [0,d]);});;
    var chunk = new Uint8Array(C.OLED_CHUNK+1);

    chunk[0] = C.OLED_CHAR;
    for (var p=0; p<this.buffer.length; p+=C.OLED_CHUNK) {
      chunk.set(new Uint8Array(this.buffer,p,C.OLED_CHUNK), 1);
      i2c.writeTo(addr, chunk);
    }
  };

  // set contrast, 0..255
  oled.setContrast = function(c) { i2c.writeTo(addr, 0, 0x81, c); };

  // set off
  oled.off = function() { i2c.writeTo(addr, 0, 0xAE); }

  // set on
  oled.on = function() { i2c.writeTo(addr, 0, 0xAF); }

  // return graphics
  return oled;
};

exports.connectSPI = function(spi, dc,  rst, callback, options) {
  update(options);
  var cs = options?options.cs:undefined;
  var oled = Graphics.createArrayBuffer(C.OLED_WIDTH,initCmds[4]+1,1,{vertical_byte : true});


  if (rst) {
    //digitalPulse(rst,0,10);
    for(var i = 0; i<10; i++){
      digitalWrite(rst,0);
      digitalWrite(rst,1);
    }
  }

  setTimeout(function() {
    if (cs) digitalWrite(cs,0);
    // configure the OLED
    digitalWrite(dc,0); // command
    spi.write(initCmds);
    digitalWrite(dc,1); // data
    if (cs) digitalWrite(cs,10);
    // if there is a callback, call it now(ish)
    if (callback !== undefined) setTimeout(callback, 10);
  }, 50);

  // write to the screen
  oled.flip = function() {
    // set how the data is to be sent (whole screen)
    if (cs) digitalWrite(cs,0);
    digitalWrite(dc,0);// command
    spi.write(flipCmds);
    digitalWrite(dc,1);// data
    spi.write(this.buffer);
    if (cs) digitalWrite(cs,1);
  };

  // set contrast, 0..255
  oled.setContrast = function(c) {
    if (cs) digitalWrite(cs,0);//cs.reset();
    spi.write(0x81,c,dc);
    if (cs) digitalWrite(cs,1);//cs.set();
  };

  // set off
  oled.off = function() {
    if (cs) digitalWrite(cs,0);//cs.reset();
    spi.write(0xAE,dc);
    if (cs) digitalWrite(cs,1);//cs.set();
  };

  // set on
  oled.on = function() {
    if (cs) digitalWrite(cs,0);//cs.reset();
    spi.write(0xAF,dc);
    if (cs) digitalWrite(cs,1);//cs.set();
  };

  // return graphics
  return oled;
};

• #5

MaBe
But, the initial action of SPI and Graphics module must be in the onInit() function. why?
And the RST pin must be connected! The cs option must be defined too.

because connectSPI send some init commands to make the OLED work correct.
```
....  
setTimeout(function() {
    // configure the OLED
    initCmds.forEach(function(d) {i2c.writeTo(addr, [0,d]);});;
  }, 50);
....
```
• #6

Wilberforce

@user73896
We are still in the process of debugging the ESP32 code.

Please can you confirm the following

a. I'm surprised this did not work:
cs.reset() and cs.set()

Please can you re-test?

b. digitalPulse(rst,0,10)

I'm not sure if this has been implemented - @JumJum - can you recall?
• #7

Wilberforce

comfirmed that D21.reset() does not turn off.
Raised:
https://github.com/espruino/Espruino/issues/1103

• #8

Aifer in reply to @Wilberforce

in mySSD1360.js, in exports.connectSPI function ,

if (rst) {
    digitalPulse(rst,0,10);
    /*
    for(var i = 0; i<10; i++){
      digitalWrite(rst,0);
      digitalWrite(rst,1);
    }
    */
  }

the OLED dosn't work.

then , try

if (rst) {
    //digitalPulse(rst,0,10);
    for(var i = 0; i<10; i++){
      digitalWrite(rst,0);
      digitalWrite(rst,1);
    }
  }

the OLDE works well.

so, I think digitalPulse(rst,0,10) doesn't works correctly.

• #9

Aifer

I' sorry, pin.set() and reset() can work well, D21.set and reset works on my widora v5.0 ESP32 board.
• #10

JumJum

digitalPulse(rst,0,10) sends one pulse to gnd for 10 msecs
Is this what you need, or do you need 10 pulses ?
• #11

Wilberforce

@jumjum
I thînk the line came from an existing module.

I think it is meant to set to low for 10 ms then finish in the high state. That's how I read that reference documentation.
• #12

JumJum

If there is a pulse only, replacing this by 10 times on/off is a bit strange.
• #13

Aifer in reply to @JumJum

eg. digitalPulse(A0,1,5); pulses A0 high for 5ms. digitalPulse(A0,1,[5,2,4]); pulses A0 high for 5ms, low for 2ms, and high for 4ms.

It seems that digitalPulse(rst,0,10) sets rst pin( rst = 1) , and then resets it for 10ms(rst = 0), at last sets it again(rst = 1).

Yet, it doesn't work.
• #14

MaBe

Hi @Aifer,

check the state of your rest pin, should be "input_pullup" to make digitalPulse(rst,0,10) work

• #15

Aifer in reply to @MaBe

Hi, @MaBe
In SSD1306.js / connectSPI() function

if (rst) {
    pinMode(rst, "input_pullup");
    digitalPulse(rst,0,10);
  }

Not work.

if (rst) {
    pinMode(rst, "input_pullup");
    digitalPulse(rst,1,10);
  }

Work well.

if (rst) {
    //pinMode(rst, "input_pullup");
    digitalPulse(rst,1,10);
  }

Work well.

if (rst) {
    digitalWrite(rst,1);
    digitalWrite(rst,0);
    setTimeout(function(){ digitalWrite(rst,1); },10);
  }

Work well.

if (rst) {
    digitalWrite(rst,0);
    digitalWrite(rst,1);
    setTimeout(function(){ digitalWrite(rst,0); },10);
  }

Not work.

if (rst) {
    pinMode(rst, "input_pullup");
    digitalWrite(rst,1);
    digitalWrite(rst,0);
    setTimeout(function(){ digitalWrite(rst,1); },10);
  }

Work well.

if (rst) {
    pinMode(rst, "input_pullup");
    digitalWrite(rst,0);
    digitalWrite(rst,1);
    setTimeout(function(){ digitalWrite(rst,0); },10);
  }

Work well.

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SSD1306 doesn't work on ESP32?

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SSD1306 doesn't work on ESP32?

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