Hardware TWI/I2C Example

RE: Hardware TWI/I2C Example

MartinBL — Thu, 26 Nov 2015 12:08:54 GMT

Hi. @NewToNordic has the answer below. I have updated my initial answer with a step-by-step explanation.

RE: Hardware TWI/I2C Example

MartinBL — Thu, 26 Nov 2015 12:07:24 GMT

Hi. You were right in your answer below. For the record I'm using Keil uVision (MDK) v5.12.

RE: Hardware TWI/I2C Example

Andrew J. — Wed, 25 Nov 2015 21:45:33 GMT

Hey Everyone,

I believe the issue might lie in the Keil packs for nrf_libraries and nrf_drivers. I used the second newest versions (made in July) with Martin's new TWI example (V3) and it was able to build.

Not sure if its the best solution but it worked.

Thanks, Andrew

RE: Hardware TWI/I2C Example

SDB — Sun, 22 Nov 2015 16:17:23 GMT

Hi martin I want to connect mpu9150 chipset via I2C. But i can't find the project what i want.

I have tested your project. But i have encountered same problem as below...

Build target 'nrf51422_xxac' compiling main.c... ....\main.c(55): warning: #223-D: function "CONCAT_2" declared implicitly const nrf_drv_twi_t p_twi_instance = NRF_DRV_TWI_INSTANCE(1); // Set up TWI instance 1 with default values ....\main.c(55): error: #20: identifier "NRF_TWI" is undefined

My MDK version is V5.14

Thanks.

RE: Hardware TWI/I2C Example

Andrew J. — Fri, 20 Nov 2015 22:59:02 GMT

Hi Martin,

What version of MDK are you currently using? I am on 5.17. I was hoping to try 5.16a, the current version when you posted, but I think I have to purchase the full version to do so...

Could you provide your current configurations (MDK version, SDK version, etc.) or what configurations you know work?

Thanks, Andrew

RE: Hardware TWI/I2C Example

Andrew J. — Sun, 15 Nov 2015 00:08:01 GMT

Thanks Martin. Let me know when it has been resolved.

Using the method you provided, it appears that I need to add a lot of include paths to make this code work. Still working on it.

RE: Hardware TWI/I2C Example

MartinBL — Sat, 14 Nov 2015 19:13:53 GMT

I tried to run the example myself now and ran into the same problems as you. It looks like there has been an update to the MDK or Keil packs that has messed with what files are included. You need to make sure that it is only the drivers found in "your_SDK9_folder\components" that is used. Open managed run-time environment in Keil and deselect the TWI drivers there. I attached an updated example, v3, that works on my system at least. I need to investigate further to find out exactly what caused this.

RE: Hardware TWI/I2C Example

Andrew J. — Sat, 14 Nov 2015 17:57:38 GMT

Hi Martin. I believe so.

C:\Keil_v5\ARM\Device\Nordic\examples\peripheral\twi_simple_SDK9.0.0_v2\pca10028\arm5_no_packs\twi_simple_SDK9.0.0_v2.uvprojx

*I'm using Dynastream's N5 Starter kit

My includes are:

....
........\bsp
..........\components\libraries\util
..........\components\device
..........\components\toolchain
..........\components\drivers_nrf
..............\Pack\ARM\CMSIS\4.5.0\CMSIS\Include

RE: Hardware TWI/I2C Example

MartinBL — Sat, 14 Nov 2015 08:28:04 GMT

Sounds like a path issue. Did you extract the example so that the file path looks exactly like the one in my first comment?

RE: Hardware TWI/I2C Example

Andrew J. — Fri, 13 Nov 2015 21:06:51 GMT

Hi! I am struggling to build this code. I'm getting errors like:

....\main.c(55): warning: #223-D: function "CONCAT_2" declared implicitly const nrf_drv_twi_t p_twi_instance = RF_DRV_TWI_INSTANCE(1); // Set up TWI instance 1 with default values ....\main.c(55): error: #20: identifier "NRF_TWI" is undefined const nrf_drv_twi_t p_twi_instance =

These appear to be basic TWI macros used by the libraries but definitions for variables like NRF_TWI cannot be found.

I am wondering if there is a file path issue that needs to be resolved. Or if this code does not apply to my scenario. I'm using SDK 9.0, nRF51422, Keil_V5, and soft device s110.

Any suggestions?

RE: Hardware TWI/I2C Example

MartinBL — Tue, 01 Sep 2015 08:33:00 GMT

SDK 8 introduced some pretty big changes in the way drivers and libraries are structured so this will require some work (maybe a lot). The main thing to remember, though, is that the SDK 8+ drivers are made for 3rd revision nRF51s and will not work on earlier revisions. If you have a 3rd revision IC and want to use SDK 7.2 I can't see any reasons why it wouldn't work if you are willing to do the work.

RE: Hardware TWI/I2C Example

danbujak — Mon, 31 Aug 2015 18:53:18 GMT

I've been using your example with 8.1 for a while now and everything seems to be working well, so thank you very much for sample. Do you know if this library would work with SDK 7.2? I know the TWI library that came with that SDK had some issues.

RE: Hardware TWI/I2C Example

MartinBL — Mon, 24 Aug 2015 07:10:57 GMT

The driver in SDK 9 configures the SDA and SCL pins with internal pullups. However, the pull ups are 13 kOhm, which is quite high, so I would recommend a couple of external ones as well. Especially if you are going to use clock speeds above 100 kHz.

RE: Hardware TWI/I2C Example

danbujak — Fri, 21 Aug 2015 14:50:13 GMT

Does this require pull-ups? The SDA line looks like its being pulled up but the SCL isnt

RE: Hardware TWI/I2C Example

MartinBL — Fri, 21 Aug 2015 07:28:08 GMT

Yes, the SDK 9 driver only has a minor bug fix.

RE: Hardware TWI/I2C Example

danbujak — Fri, 21 Aug 2015 01:44:47 GMT

This driver should be compatible with SDK8.1 as well, correct?

RE: Hardware TWI/I2C Example

samet kocatepe — Thu, 20 Aug 2015 09:04:43 GMT

thanks martin. :)

RE: Hardware TWI/I2C Example

MartinBL — Thu, 20 Aug 2015 09:00:51 GMT

Where did you extract the example? The folder path to your example .uvprojx file should look like this: "your_SDK9_folder\examples\peripheral\twi_simple_SDK9.0.0_v2\pca10028\arm5_no_packs\twi_simple_SDK9.0.0_v2.uvprojx". The example is meant to be used with the SDK folder structure in the .zip file here. It is not intended for use with the pack installer.

RE: Hardware TWI/I2C Example

samet kocatepe — Thu, 20 Aug 2015 08:46:50 GMT

hi martin thank for fast reply. when i open your example and compile , i faced a build error like image screenshot. can you give any suggest for this.

RE: Hardware TWI/I2C Example

MartinBL — Thu, 20 Aug 2015 08:01:23 GMT

I have made a simple example using the latest TWI driver in SDK 9. It is very basic;

It sets up and configure a TWI instance.
Transmits dummy bytes to addresses 0x00 to 0x7F and listens for a response from other TWI devices on the bus.
Lights a LED if a device is found.

I have used this example for a while myself just to get me started on a new TWI project. It is simple, but very handy just to see if you have everything connected and set up correctly.

Test examples for SDK 0.9.2, 10.0.0, and 11.0.0: twi-find-devices-on-bus.

twi_simple_SDK9.0.0_v2.zip

EDIT: The folder path to your example .uvprojx file should look like this: "your_SDK9_folder\examples\peripheral\twi_simple_SDK9.0.0_v2\pca10028\arm5_no_packs\twi_simple_SDK9.0.0_v2.uvprojx". The example is meant to be used with the SDK folder structure in the .zip file here. It is not intended for use with the pack installer.

EDIT 2: Updated example: twi_simple_SDK9.0.0_v3.zip

EDIT 3: Response to the questions and comments below regarding build errors:

@NewToNordic is right in his answer below. The latest pack driver and library versions are v3.1.0 with e.g. new TWI drivers that are not compatible with the older examples. This is how I solved it:

Choose "fixed" from the Selection drop down list.
Choose version 3.0.1.

If you get an error complaining about "nrf_drv_config_validation.h": No such file or directory, then just comment out the line in nrf_drv_config.h.
Then finally enable TWI 1 in nrf_drv_config.h by writing #define TWI1_ENABLED 1.

This worked for me with the 2nd version example in my initial answer and my nRF51 DK kit.