SSD1306/SH1106 does not work in custom board with nrf52832

[Illia Alexandrov]

Hello

I made a project based on this guy's example taking the same settings, but considering the specifics of nrf52. Since it's a relatively recent solution, I thought it should work. devzone.nordicsemi.com/.../nrf52840-dk---ssd1306---display. github.com/.../test_zephyr_oled . This project was built and flashed but I don't see anything.

I work with sh1106 but for now, I choose ssd1306 to see at least something. If you know what exactly needs to be written and selected for sh1106 to work, I'd be grateful for advice (maybe we can just change the page offset in ssd1306 to make it work properly in sh1106?).

Here is my overlay:

/ {
    chosen {
        zephyr,display = &ssd1306;
    };
};

&pinctrl {
    i2c0_default: i2c0_default {
		group1 {
			psels = <NRF_PSEL(TWIM_SDA, 0, 22)>,
				<NRF_PSEL(TWIM_SCL, 0, 23)>;
		};
	};

	i2c0_sleep: i2c0_sleep {
		group1 {
			psels = <NRF_PSEL(TWIM_SDA, 0, 22)>,
				<NRF_PSEL(TWIM_SCL, 0, 23)>;
			low-power-enable;
        };
    };
};

&i2c0 {
    compatible = "nordic,nrf-twi";
    status = "okay";
    pinctrl-0 = <&i2c0_default>;
    pinctrl-1 = <&i2c0_sleep>;
    pinctrl-names = "default", "sleep";
    clock-frequency = <I2C_BITRATE_FAST>;


    ssd1306: ssd1306@3c {
        compatible = "solomon,ssd1306fb";
        reg = <0x3c>;
        height = <64>;
        width = <128>;
        segment-offset = <0>;
        page-offset = <0>;
        display-offset = <0>;
        multiplex-ratio = <63>;
        prechargep = <0x22>;
        com-invdir;
        segment-remap;
    };
};

I work with a custom board with nRF52832 chip and with NCS 2.8.0. 

Help me please

[Kenneth]

Hello,

You can try to enable logging from the low level nrfx twim driver to see if that provide more information:
https://docs.nordicsemi.com/bundle/ncs-2.9.0/page/kconfig/index.html#CONFIG_NRFX_TWIM_LOG 

But the best is possible to connect a logic analyzer to check if there are pull-up on the pins and you check to see if the address and data is acked or nacked.

Kenneth

[Illia Alexandrov]

Hello, thanks for the reply. On the CONFIG_NRFX_TWIM_LOG line in the conf I get: CONFIG_NRFX_TWIM_LOG was assigned the value y, but got the value n. Missing dependencies:
(NRFX_TWIM && LOG && HAS_NRFX) || (NRFX_TWIM && LOG && HAS_NRFX && 0)

If I tried CONFIG_NRFX_TWI_LOG=y I got this 

There is a pull-up on the pins. I don't have a logic analyzer, so I try to watch it with an oscilloscope. I couldn't see any data transfer on the pins.

[Kenneth]

The nrfx_twi_xfer() seems to be success. Are you able to find where in ssd1306_init_device() it seems to fail? What if you disconnect the display, what is the error then?

Kenneth

[Illia Alexandrov]

Hello.

If I physically disconnect the display, I get the same logs.

I don't know how to get to the driver files, but I found this in ssd1306_init_device() 

from here https://github.com/zephyrproject-rtos/zephyr/blob/main/drivers/display/ssd1306.c#L393

By the way, is it ok that I look at the TWI logs, but I can’t look at the TWIM logs, although in pinctrl I have TWIM on the I2C pins?

[Kenneth]

You can also search for the implementation of the ssd1306_init_device() to see which api that fail in specific. Though from your simply experiment it seems that there is no ack on the i2c interface, are you sure pins are connected properly, module is powered, ground is common, and that the module is in i2c mode (and not spi or other mode) with correct i2c address?

The nRF52832 support two different hardware implementation of twi (i2c)

compatible = "nordic,nrf-twi"; 
compatible = "nordic,nrf-twim"; 

I don't expect they make any difference here.

Kenneth

[Illia Alexandrov]

Yes, pins are connected properly, and the module is powered. I also tried to turn on this screen on another device and it works fine.

[Kenneth]

My best suggestion is to connect a logic analyzer then, and compare working and failing, this will narrow down the cause quite a bit.

Kenneth