Using I2C & GPIOTE interrupt with soft device enabled

RE: Using I2C & GPIOTE interrupt with soft device enabled

Jeong Hyun Seok — Tue, 26 Apr 2016 04:55:32 GMT

Thanks a lot. It was great help.

also I didnot get what Ole Morten means. Means we don't need ppi in twi anymore to newest chip?

RE: Using I2C & GPIOTE interrupt with soft device enabled

la-ble — Fri, 05 Dec 2014 21:43:39 GMT

This is an amazing help. Can you share your updated tw_hw_master.c file with the appropriate sd_ppi_* calls swapped in? Maybe on github? I feel like this is something nordic should provide with each SDK release.

RE: Using I2C & GPIOTE interrupt with soft device enabled

Ole Morten — Tue, 11 Mar 2014 14:56:59 GMT

You can refer to this example for how twi_hw_master can be modified to use the shorts: https://github.com/NordicSemiconductor/nrf51-ble-app-lbs/tree/twi-display-5.1.0

RE: Using I2C & GPIOTE interrupt with soft device enabled

Jason De Lorme — Fri, 07 Mar 2014 12:11:52 GMT

Great, thank you.

RE: Using I2C & GPIOTE interrupt with soft device enabled

Ole Morten — Fri, 07 Mar 2014 10:37:57 GMT

Sorry, you didn't write which chip you were using, so I assumed nRF51822. For the nRF51422, the equivalent version to FA is your E0. You can refer to this PCN: https://www.nordicsemi.com/eng/nordic/download_resource/26303/1/9501341

Also, for the nRF51422, you should use this PAN, not the one I originally linked to (although all hardware problems are the same): https://www.nordicsemi.com/eng/nordic/Products/nRF51422/nRF51422-PAN/26307

RE: Using I2C & GPIOTE interrupt with soft device enabled

Jason De Lorme — Fri, 07 Mar 2014 00:28:44 GMT

Thanks for the tip, Ole. I'm just getting around to looking into this. What portion of the chip identification can tell me if the revision is FA or higher? On my sample chips I have:

N51422 QFAAE0 1347AA

Thank you!

RE: Using I2C & GPIOTE interrupt with soft device enabled

Ole Morten — Mon, 17 Feb 2014 14:53:07 GMT

Thanks for posting this write-up! I'd just like to highlight one thing: The usage of the PPI in the TWI implementation is actually due to item 36 in the PAN for nRF51822 or this PAN for nRF51422:

The following shortcuts are not implemented:

Short-cut between BB event and SUSPEND task.

Short-cut between BB event and STOP task.

As shown in the PAN document, this have been fixed on the second revision chips (nRF51822 FA, or nRF51422 E0 and later), and hence, if you use and target such chips, you can instead use the shortcuts directly, without using the PPI at all. This should save you both the PPI channels and some hassle.