Problem sending data via TWI - Fatal error

RE: Problem sending data via TWI - Fatal error

daubsi — Tue, 05 Jan 2021 10:23:17 GMT

Thanks Edvin, I eventually managed to get a fully working example!

If anyone is interested or in need of a working example of using the u8g2 library on a nRF 52 DK please have a look here:

https://github.com/olikraus/u8g2/issues

and/or here:

github.com/.../u8g2_nrf52

RE: Problem sending data via TWI - Fatal error

Edvin — Mon, 04 Jan 2021 10:38:18 GMT

Hello,

Glad to hear that you found the root cause of your issue. Yes. The 0x8202 means NRF_ERROR_DRV_TWI_ERR_DNACK. Why this was returned was probably a bit random, if the device was not configured for TWI.

Best of luck with the garbled output. Make sure that you check the datasheet of the display, so that you send the data in the way that the screen expects to receive it.

Best regards,

Edvin

RE: Problem sending data via TWI - Fatal error

daubsi — Sat, 02 Jan 2021 15:29:06 GMT

I turned out the problem was because I was not actually initializing the u8g2 in i2c mode but presumably in SPI mode.

Sniffing the i2c traffic on an Arduino showed the following signals

Whereas on the nRF52 DK it was

So that middle part was clearly missing. In the end it turned out I had to call u8g2_Setup_sh1106_i2c_128x64_noname_f() instead of u8g2_Setup_sh1106_128x64_noname_f....

The display now initialized but has a garbled output. I will work on this now. The TWI part of the SDK seems to work perfectly now

RE: Problem sending data via TWI - Fatal error

daubsi — Fri, 01 Jan 2021 19:49:29 GMT

The actual error I receive it 0x8202 by the way: NRF_ERROR_DRV_TWI_ERR_DNACK

I also tried setting the frequency to 400 kHz but no change in the result.