Is there no I2C/TWI peripheral example in the SDK documentation?

RE: Is there no I2C/TWI peripheral example in the SDK documentation?

Kevin — Fri, 12 Jun 2015 21:27:43 GMT

@Stian turns out it was a completely different issue. I had always flashed the softdevice from Keil and for some reason I was getting those errors after adding the TWI library and trying to flash the softdevice. I went back to only flashing the softdevice from nRFgo Studio and voila, no problems. Thanks for your quick response!

RE: Is there no I2C/TWI peripheral example in the SDK documentation?

Kevin — Fri, 12 Jun 2015 16:30:36 GMT

Thanks for pointing out that there is a new driver in 8.1, @Stian. I'll try it out today, and hopefully it will resolve my nrf_delay problem :)

RE: Is there no I2C/TWI peripheral example in the SDK documentation?

Stian Røed Hafskjold — Fri, 12 Jun 2015 07:22:13 GMT

I agree that it should definitely be a TWI example in the SDK. However, there is a TWI driver in the SDK8.0 (and a completely new and improved driver in SDK8.1), which has twi_master_init and twi_master_transfer functions, so I wouldn't say that the TWI support is dropped entirely.

RE: Is there no I2C/TWI peripheral example in the SDK documentation?

Kevin — Thu, 11 Jun 2015 17:15:56 GMT

I'm having a lot of trouble using TWI with the S110 softdevice and v8.0 sdk. Specifically, the softdevice cannot find nrf_delay.h. The workaround has been to not include the twi while compiling the softdevice, then include it when compiling application code. I understand there isn't a need for TWI in the sdk examples since not TWI slave is on the new board, but, it seems like the consequence is inadvertently dropping TWI support entirely...

RE: Is there no I2C/TWI peripheral example in the SDK documentation?

Bouke — Tue, 31 Mar 2015 07:38:39 GMT

I can confirm that SPI is more energy efficient than TWI in general.

RE: Is there no I2C/TWI peripheral example in the SDK documentation?

Stian Røed Hafskjold — Mon, 30 Mar 2015 15:54:03 GMT

The TWI example was removed in SDK 7 after the introduction of the new development kit, because there was no TWI slave on the board that any TWI master examples could use.

You can of course use the TWI examples from SDK 6.1.0: developer.nordicsemi.com/.../a00051.html.

It might need some modifications to work with the TWI hardware driver in SDK 8: developer.nordicsemi.com/.../a00014.html

I guess the general tradeoffs are number of lines needed and speed. I believe the SPI would require less power because the execution time is lower, but I can not confirm that. The TWI hardware should be as reliable as the SPI hardware, and it will be available in the future.