need help with oled and NRF52 DK

[phob]

Hi, i was interfacing oled with nrf52 board. I got some example and modified bit to use it with GCC. But it is now working. Oled not at all starting. oled is 0.96 inch, I2C based 128x64. Vdd = 5v sda = p0.26 scl = p0.27

Here is code github.com/.../

[Jørgen Holmefjord]

Hi,

The problem seems to be that you are using the TWI driver in non-blocking mode, but you do not have any mechanism implemented to make sure that the previous transfer is done before starting a new transfer. If you check the return code of your calls to nrf_drv_twi_tx() in ssd1306_command(), you will see that you get a lot of error code 0x11 - NRF_ERROR_BUSY. This leads to that the commands is not sent to the OLED.

A simple fix to this problem is to switch to blocking mode for the TWI instance. This is done by passing NULL to event_handler argument of nrf_drv_twi_init().

Best regards,

Jørgen

[phob]

I checked with blocking mode, but it didn't work for me. Do i have to change jumper anywhere? I checked voltage and its proper, but like other lcd's which glow backlight, but with oled backlight is not coming. Do we have any example to refer?

[Jørgen Holmefjord]

Yes, the backlight is enables in initialization (at least on my device). Do you get any error codes from the calls to nrf_drv_twi_tx? Have you checked that you are using the correct address for the device? You can scan for TWI devices using the TWI scanner example.

[phob]

No, I think my code is not working at all. Even if i do LED ON then also no effect. I saw once LED backlight was ON, but later no such effect. I have updated code on github and link shared in 1st post.

[Jørgen Holmefjord]

The code from your GitHub is working with my display if I change the I2C address from 3D to 3C. Are you sure the OLED is powered correctly?