I2C not working on SSD1327

[Andrzej1000]

Hi. I have SSD1327 128x128 form waveshare. The library working on SPI. Unfortunately I2C does not work. The display does not light anything. I checked example code from waveshare and it works. Olikraus could you check what's going on? Thanks...

[olikraus]

You say, SPI works, but I2C doesn't work, right?

[Andrzej1000]

Yes. SPI working but I2C not work.

[olikraus]

ok, I am still confused (also by your reply here #397): Does you display work with u8g2 in SPI mode?

[Andrzej1000]

SPI working with your library: //U8G2_SSD1327_MIDAS_128X128_1_4W_SW_SPI u8g2(U8G2_R0, / clock=/ 13, / data=/ 11, / cs=/ 10, / dc=/ 9, / reset=/ 8); //U8G2_SSD1327_MIDAS_128X128_1_4W_HW_SPI u8g2(U8G2_R0, / cs=/ 10, / dc=/ 9, / reset=/ 8); //U8G2_SSD1327_EA_W128128_1_4W_HW_SPI u8g2(U8G2_R0, / cs=/ 10, / dc=/ 9, / reset=/ 8);

I2C with library U8G2 not working: //U8G2_SSD1327_EA_W128128_1_SW_I2C u8g2(U8G2_R0, / clock=/ 5, / data=/ 4, / reset=/ U8X8_PIN_NONE); //U8G2_SSD1327_EA_W128128_1_HW_I2C u8g2(U8G2_R0, / reset=/ U8X8_PIN_NONE);

[olikraus]

ok. Did you connect DC input line of the display to GND (so that the default I2C address is 0x78)?

[olikraus]

I crosschecked the software. Everything should be ok.

[Andrzej1000]

OK. It works. DC connected to GND. Thank you very much !!! Please, make init string U8G2 for the default address without this connecting...?

[olikraus]

In I2C mode, you must connect connect the DC input to either low or high, you can not leave it open. If open, then the display will draw much more current and the I2C address is unpredictable. All in all you should follow the wiring instructions in chapter 8 of the SSD1327 controller datasheet. Depending on the level applied to DC input, you should inform U8g2 about the selected I2C address.

See here: https://electronics.stackexchange.com/questions/7179/is-it-really-a-bad-idea-to-leave-an-mcu-input-pin-floating and here: https://www.quora.com/Why-is-it-not-advised-to-float-inputs-to-CMOS-gates-under-any-circumstances#

In general U8g2 always uses the lowest I2C address allowed by the display. I would personally call this a useful default.

[Andrzej1000]

Thanks for the clarification.

[olikraus]

:-)

[s1sm1x]

Hi olikraus,

Still on this issue, I'm having a lot of trouble on gettin the 128x128 SD1327 1.5' module (waveshare) to work. After reading every post about SD1327 written from you, I still can't display as I want. I'm using a nodemcu compatible board: Wemos D1 mini. I use this code to test several font sizes:

include

include

include

/* U8g2lib Example Overview: Frame Buffer Examples: clearBuffer/sendBuffer. Fast, but may not work with all Arduino boards because of RAM consumption Page Buffer Examples: firstPage/nextPage. Less RAM usage, should work with all Arduino boards. U8x8 Text Only Example: No RAM usage, direct communication with display controller. No graphics, 8x8 Text only.

This is a frame buffer example. */

// Please UNCOMMENT one of the contructor lines below // U8g2 Contructor List (Frame Buffer) // The complete list is available here: https://github.com/olikraus/u8g2/wiki/u8g2setupcpp // Please update the pin numbers according to your setup. Use U8X8_PIN_NONE if the reset pin is not connected //U8G2_NULL u8g2(U8G2_R0); // null device, a 8x8 pixel display which does nothing //U8G2_SH1106_128X64_NONAME_F_HW_I2C u8g2(U8G2_R0, / reset=/ U8X8_PIN_NONE);

U8G2_SSD1327_EA_W128128_1_SW_I2C u8g2(U8G2_R0, / clock=/ D1, / data=/ D2, / reset=/ U8X8_PIN_NONE); //U8G2_SSD1327_EA_W128128_1_HW_I2C u8g2(U8G2_R0, / reset=/ U8X8_PIN_NONE);

// End of constructor list

define MINI_LOGO

void setup(void) { //pinMode(9, OUTPUT); //digitalWrite(9, 0); // default output in I2C mode for the SSD1306 test shield: set the i2c adr to 0 Serial.begin(115200);

u8g2.begin(); }

void draw1(void) { u8g2.clearBuffer(); u8g2.setFontDirection(0); u8g2.setFont(u8g2_font_inb46_mf); u8g2.drawStr(0, 63, "1111"); u8g2.sendBuffer(); Serial.println("46"); delay(1000); u8g2.clearBuffer(); u8g2.setFontDirection(0); u8g2.setFont(u8g2_font_inb49_mf); u8g2.drawStr(0, 63, "1111"); u8g2.sendBuffer(); Serial.println("49"); delay(1000); u8g2.clearBuffer(); u8g2.setFontDirection(0); u8g2.setFont(u8g2_font_inb53_mf); u8g2.drawStr(0, 63, "1111"); u8g2.sendBuffer(); Serial.println("53"); delay(1000); u8g2.clearBuffer(); u8g2.setFontDirection(0); u8g2.setFont(u8g2_font_inb57_mn); u8g2.drawStr(0, 63, "1111"); u8g2.sendBuffer(); Serial.println("57"); delay(1000); u8g2.clearBuffer(); u8g2.setFontDirection(0); u8g2.setFont(u8g2_font_inb63_mn); u8g2.drawStr(0, 63, "1111"); u8g2.sendBuffer(); Serial.println("63"); delay(1000); } void loop(void) {

drawLogo(); u8g2.sendBuffer(); draw1();

delay(1000); }

But at the end, I only get a small portion of the display to work horizontally at the top like the :

The "1111" string seems to be printed, but the numbers don't show on the whole screen. The final idea is to display time ("12:12") as big as it can, That's why I chose a 1.5' display instead of the available 0.91' ou 0.96'. The orange wire on the right is connecting DC to GND. My final address is 0x3C and not 0x78 you mentioned earlier in this issue. Is this information useful? If needed, I can change the address but I don't know where... Once you have availability, can you say where do I change it?

Could you help me? This is for a direct application project and I'm have been freaking out with his type of oleds. But, at this time, I feel that I'm pretty close to a working solution!

Thank you for the paid attention,

Pedro Oliveira / s1sm1x

[olikraus]

Use the _F_ constructor: U8G2_SSD1327_EA_W128128_F_SW_I2C, see also here: https://github.com/olikraus/u8g2/wiki/u8g2setupcpp#buffer-size You must not use sendBuffer together with the _1_ constructor.

[olikraus]

Or here: https://github.com/olikraus/u8g2/blob/master/doc/faq.txt#L134

[s1sm1x]

Use the _F_ constructor: U8G2_SSD1327_EA_W128128_F_SW_I2C, see also here: https://g

include

include

include

//U8G2_NULL u8g2(U8G2_R0); // null device, a 8x8 pixel display which does nothing //U8G2_SH1106_128X64_NONAME_F_HW_I2C u8g2(U8G2_R0, / reset=/ U8X8_PIN_NONE);

//U8G2_SSD1327_EA_W128128_1_SW_I2C u8g2(U8G2_R0, / clock=/ D1, / data=/ D2, / reset=/ U8X8_PIN_NONE); //U8G2_SSD1327_EA_W128128_1_HW_I2C u8g2(U8G2_R0, / reset=/ U8X8_PIN_NONE); //U8G2_SSD1327_EA_W128128_1_2ND_HW_I2C u8g2(U8G2_R0, / reset=/ U8X8_PIN_NONE); //after olikraus U8G2_SSD1327_EA_W128128_F_SW_I2C u8g2(U8G2_R0, / clock=/ D1, / data=/ D2, / reset=/ U8X8_PIN_NONE);

// End of constructor list

define MINI_LOGO

void setup(void) { //pinMode(9, OUTPUT); //digitalWrite(9, 0); // default output in I2C mode for the SSD1306 test shield: set the i2c adr to 0 Serial.begin(115200);

u8g2.begin();

} void draw1(void) { u8g2.clearBuffer(); u8g2.setFont(u8g2_font_ncenB14_tr); u8g2.drawStr(0,20,"Hello World!"); u8g2.sendBuffer(); delay(1000); u8g2.clearBuffer(); u8g2.setFontDirection(0); u8g2.setFont(u8g2_font_inb46_mf); u8g2.drawStr(50, 50, "1111"); u8g2.sendBuffer(); Serial.println("46"); delay(2000); u8g2.clearBuffer(); u8g2.setFontDirection(0); u8g2.setFont(u8g2_font_inb49_mf); u8g2.drawStr(50, 50, "1111"); u8g2.sendBuffer(); Serial.println("49"); delay(2000); u8g2.clearBuffer(); u8g2.setFontDirection(0); u8g2.setFont(u8g2_font_inb53_mf); u8g2.drawStr(50, 50, "1111"); u8g2.sendBuffer(); Serial.println("53"); delay(1000); u8g2.clearBuffer(); u8g2.setFontDirection(0); u8g2.setFont(u8g2_font_inb57_mn); u8g2.drawStr(50, 50, "1111"); u8g2.sendBuffer(); Serial.println("57"); delay(1000); u8g2.clearBuffer(); u8g2.setFontDirection(0); u8g2.setFont(u8g2_font_inb63_mn); u8g2.drawStr(50, 50, "1111"); u8g2.sendBuffer(); Serial.println("63"); delay(1000); } void loop(void) { // u8g2.clearBuffer(); drawLogo(); u8g2.sendBuffer(); draw1(); //u8g2.sendBuffer(); delay(1000); }

It partially write the logo, but it reset through Soft wdt with the message code:

Soft WDT reset

ctx: cont sp: 3ffffbe0 end: 3fffffd0 offset: 01b0

stack>>> 3ffffd90: 00000078 3fffff30 0000001c 00000030
3ffffda0: 40106538 00000001 00000040 feefeffe
3ffffdb0: 40106538 00000001 00000040 40214f9a
3ffffdc0: 40106538 00000001 00000040 40214f9a
3ffffdd0: 40106538 00000001 00000040 40214f9a
3ffffde0: 40106538 00000001 00000040 40214f9a
3ffffdf0: 40106538 00000001 000000ff 40106569
3ffffe00: 40106538 00000001 000000ff 40214f9a
3ffffe10: 40106538 00000000 00000005 40214f9a
3ffffe20: 00000091 00000001 00000000 00000008
3ffffe30: 000000bc 000000ff 3ffee900 40214a82
3ffffe40: 000000bc 000000ff 3ffee900 402019f2
3ffffe50: 000000bc 000000ff 3ffee900 40201a14
3ffffe60: 000000bc 00000000 3ffee900 40201a5b
3ffffe70: 3fffff50 3ffef1a4 3ffee900 40201aa4
3ffffe80: 00000018 3ffef1a8 3ffee900 40201b59
3ffffe90: 00000018 3ffef1a4 3ffee900 4021502b
3ffffea0: 3ca03c0b 000000af 3ffee900 40201c23
3ffffeb0: 00000018 00000020 3ffee900 40201d25
3ffffec0: 3ffef1a4 00000000 00000000 000000fb
3ffffed0: 3fffff50 00000001 3ffee900 402149a9
3ffffee0: 00000000 3ffee900 3ffee96c 40201e8e
3ffffef0: 0000000e 00000000 00000010 3ffeeab4
3fffff00: 00000000 0000001a 3ffee900 40201ef8
3fffff10: 8fae16b2 0000000a 00000064 00000001
3fffff20: 00000002 0000000f 3ffee900 40201ef8
3fffff30: 3ffef124 000f0010 3ffe8a98 00000000
3fffff40: 00000002 00000002 3ffee900 40214a08
3fffff50: 3ffeeaa4 00020010 3ffee900 00000000
3fffff60: 20a715ec 0000000b 3ffee900 40201060
3fffff70: 00000010 00000010 00000001 402147a2
3fffff80: 00000000 3ffee8f8 3ffee900 3ffef374
3fffff90: 3fffdad0 00000000 3ffee900 402010bf
3fffffa0: 3fffdad0 00000000 3ffef36c 40214e8b
3fffffb0: 3fffdad0 00000000 3ffef36c 40215814
3fffffc0: feefeffe feefeffe 3ffe85dc 401000e5
<<<stack<<<

ets Jan 8 2013,rst cause:2, boot mode:(3,7)

load 0x4010f000, len 1384, room 16 tail 8 chksum 0x2d csum 0x2d vbb28d4a3 ~ld

infinite loop inside some draw? btw it works pretty good on a 1.3' with SH1106 driver when the constructor changes.

I'm stuck on this. Can you help me pls?

Thank you for your energy and availability,

Pedro Oliveira

[s1sm1x]

Or here: https://github.com/olikraus/u8g2/blob/master/doc/faq.txt#L134

yes, I understood. Now , I'm using what you said. F version

thank you

[s1sm1x]

Use the _F_ constructor: U8G2_SSD1327_EA_W128128_F_SW_I2C, see also here: https://g

include

include

include

//U8G2_NULL u8g2(U8G2_R0); // null device, a 8x8 pixel display which does nothing //U8G2_SH1106_128X64_NONAME_F_HW_I2C u8g2(U8G2_R0, / reset=/ U8X8_PIN_NONE);

//U8G2_SSD1327_EA_W128128_1_SW_I2C u8g2(U8G2R0, /* clock=/ D1, / data=/ D2, / reset=/ U8X8_PIN_NONE); //U8G2_SSD1327_EA_W128128_1_HW_I2C u8g2(U8G2R0, / reset=_/ U8X8_PIN_NONE); //U8G2_SSD1327_EA_W128128_1_2ND_HW_I2C u8g2(U8G2R0, / reset=_/ U8X8_PIN_NONE); //after olikraus U8G2_SSD1327_EA_W128128_F_SW_I2C u8g2(U8G2R0, / clock=/ D1, / data=/ D2, / reset=*/ U8X8_PIN_NONE);

// End of constructor list

define MINI_LOGO

void setup(void) { //pinMode(9, OUTPUT); //digitalWrite(9, 0); // default output in I2C mode for the SSD1306 test shield: set the i2c adr to 0 Serial.begin(115200);

u8g2.begin();

} void draw1(void) { u8g2.clearBuffer(); u8g2.setFont(u8g2_font_ncenB14_tr); u8g2.drawStr(0,20,"Hello World!"); u8g2.sendBuffer(); delay(1000); u8g2.clearBuffer(); u8g2.setFontDirection(0); u8g2.setFont(u8g2_font_inb46_mf); u8g2.drawStr(50, 50, "1111"); u8g2.sendBuffer(); Serial.println("46"); delay(2000); u8g2.clearBuffer(); u8g2.setFontDirection(0); u8g2.setFont(u8g2_font_inb49_mf); u8g2.drawStr(50, 50, "1111"); u8g2.sendBuffer(); Serial.println("49"); delay(2000); u8g2.clearBuffer(); u8g2.setFontDirection(0); u8g2.setFont(u8g2_font_inb53_mf); u8g2.drawStr(50, 50, "1111"); u8g2.sendBuffer(); Serial.println("53"); delay(1000); u8g2.clearBuffer(); u8g2.setFontDirection(0); u8g2.setFont(u8g2_font_inb57_mn); u8g2.drawStr(50, 50, "1111"); u8g2.sendBuffer(); Serial.println("57"); delay(1000); u8g2.clearBuffer(); u8g2.setFontDirection(0); u8g2.setFont(u8g2_font_inb63_mn); u8g2.drawStr(50, 50, "1111"); u8g2.sendBuffer(); Serial.println("63"); delay(1000); } void loop(void) { // u8g2.clearBuffer(); drawLogo(); u8g2.sendBuffer(); draw1(); //u8g2.sendBuffer(); delay(1000); }

It partially write the logo, but it reset through Soft wdt with the message code:

Soft WDT reset

ctx: cont sp: 3ffffbe0 end: 3fffffd0 offset: 01b0

stack>>> 3ffffd90: 00000078 3fffff30 0000001c 00000030 3ffffda0: 40106538 00000001 00000040 feefeffe 3ffffdb0: 40106538 00000001 00000040 40214f9a 3ffffdc0: 40106538 00000001 00000040 40214f9a 3ffffdd0: 40106538 00000001 00000040 40214f9a 3ffffde0: 40106538 00000001 00000040 40214f9a 3ffffdf0: 40106538 00000001 000000ff 40106569 3ffffe00: 40106538 00000001 000000ff 40214f9a 3ffffe10: 40106538 00000000 00000005 40214f9a 3ffffe20: 00000091 00000001 00000000 00000008 3ffffe30: 000000bc 000000ff 3ffee900 40214a82 3ffffe40: 000000bc 000000ff 3ffee900 402019f2 3ffffe50: 000000bc 000000ff 3ffee900 40201a14 3ffffe60: 000000bc 00000000 3ffee900 40201a5b 3ffffe70: 3fffff50 3ffef1a4 3ffee900 40201aa4 3ffffe80: 00000018 3ffef1a8 3ffee900 40201b59 3ffffe90: 00000018 3ffef1a4 3ffee900 4021502b 3ffffea0: 3ca03c0b 000000af 3ffee900 40201c23 3ffffeb0: 00000018 00000020 3ffee900 40201d25 3ffffec0: 3ffef1a4 00000000 00000000 000000fb 3ffffed0: 3fffff50 00000001 3ffee900 402149a9 3ffffee0: 00000000 3ffee900 3ffee96c 40201e8e 3ffffef0: 0000000e 00000000 00000010 3ffeeab4 3fffff00: 00000000 0000001a 3ffee900 40201ef8 3fffff10: 8fae16b2 0000000a 00000064 00000001 3fffff20: 00000002 0000000f 3ffee900 40201ef8 3fffff30: 3ffef124 000f0010 3ffe8a98 00000000 3fffff40: 00000002 00000002 3ffee900 40214a08 3fffff50: 3ffeeaa4 00020010 3ffee900 00000000 3fffff60: 20a715ec 0000000b 3ffee900 40201060 3fffff70: 00000010 00000010 00000001 402147a2 3fffff80: 00000000 3ffee8f8 3ffee900 3ffef374 3fffff90: 3fffdad0 00000000 3ffee900 402010bf 3fffffa0: 3fffdad0 00000000 3ffef36c 40214e8b 3fffffb0: 3fffdad0 00000000 3ffef36c 40215814 3fffffc0: feefeffe feefeffe 3ffe85dc 401000e5 <<<stack<<<

ets Jan 8 2013,rst cause:2, boot mode:(3,7)

load 0x4010f000, len 1384, room 16 tail 8 chksum 0x2d csum 0x2d vbb28d4a3 ~ld

infinite loop inside some draw? btw it works pretty good on a 1.3' with SH1106 driver when the constructor changes.

I'm stuck on this. Can you help me pls?

Thank you for your energy and availability,

Pedro Oliveira

That's how it looks like.

[olikraus]

I do not know your environment, but I would say, that this is not a u8g2 problem. You probably need to increase WDT on your environment.

See here: https://techtutorialsx.com/2017/01/21/esp8266-watchdog-functions/

[s1sm1x]

I do not know your environment, but I would say, that this is not a u8g2 problem. You probably need to increase WDT on your environment.

See here: https://techtutorialsx.com/2017/01/21/esp8266-watchdog-functions/ If I use this constructor, it crashes after drawing the logo, but before drawing the strings: U8G2_SSD1327_EA_W128128_F_SW_I2C u8g2(U8G2_R0, / clock=/ D1, / data=/ D2, / reset=/ U8X8_PIN_NONE);

if I use this: U8G2_SSD1327_EA_W128128_F_HW_I2C u8g2(U8G2_R0, / clock=/ D1, / data=/ D2, / reset=/ U8X8_PIN_NONE); It doesn't print on the display but doesn't reset.

Does this give you any further information?

Thank you in advance,

Pedro Oliveira

[olikraus]

Looks like a wdt problem...